Almost Yunnanilus sp. ‘rosy’, but not

The 10 Yunnanilus loaches that I bought from Welsworld turned out to be Y. brevis, not Y. sp. ‘rosy’. The mistake is easy to make because the juvenile Y. brevis have very similar colouration to adult Y. sp. ‘rosy’ and I was not able to view the fish before collecting them. I have emailed the seller explaining the mistake and asking whether they are able to swap the loaches for the correct species. If not, I should be able to return the fish as they are not what I ordered.

Y. brevis grow to double the size of Y. sp. rosy and come from Inle Lake, so would be more suited to a 90×30×30 biotope with Danio erythromicron.

Yunnanilus sp. ‘rosy’ are here (well, almost!)

I picked up the 10 Yunnanilus sp. ‘rosy’ today from a drop-shipper, so since I was not able to observe them and they are almost certainly wild, they are not in the quarantine aquarium for the next 4-6 weeks. The water the loaches came out of was:

  • KH: 9.5 ° (170 ppm)
  • GH: 19 ° (340 ppm)
  • ammonia: 0.25 ppm
  • nitrite: 0 ppm
  • nitrate: 40 ppm
  • pH: 8.2

And, after acclimatisation, they have gone into:

  • KH: 7 ° (125 ppm)
  • GH: 19 ° (340 ppm)
  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate: 20 ppm
  • pH: 7.8

I put down the ammonia in the water they came with down to the water being of dechlorinated chloraminated water… I think I just made up a word :-S

Danios settling in

Danios are in

It has been almost a week since the Danios were added, they have settled in well and are relatively bold, but do not seem to appreciate when someone walks quickly across the room (as is expected). They certainly seem to enjoy the piece of wood, spending much of their time swimming through the holes in the base and around the stems, but do come right to the front of the glass when they notice me looking at them. The females are receiving plenty of attention from the males and one is looking considerably more plump now, so they may spawn soon.

The fish found the flow of the filter to be disturbing, so I have attempted to slow it down by wrapping filter wool around the rough sponge and placing more still between the sponge and the bio media. It seems to have helped slightly, but not enough, so I am still thinking about how to slow it down further. The stand building project has come to a bit of a stand still as I am quite lazy, but this has given me an incentive to get it going again because the external filter has a 300 lph rating compared to the 700 lph that came with the aquarium.

The fish are feeding well on frozen Daphnia and Artemia, with a supplement of high-protein granules and generic flakes. The 10 fish eat only tiny amounts, so even the smallest tub of fish food will last for years at this rate. Given that most fish food goes off in a matter of 1-6 months, it makes sense to separate it into smaller containers, freezing or chilling the majority of it until it is needed.

There have not really been any major signs of algae, I am still cleaning off mild signs of diatoms from the glass every couple of weeks, but that is it. Most of the plants are doing well, and I plan to split up one or two of the Cryptocoryne parva bunches into individual plants over the next week.

Danio margaritatus

Danio margaritatus maleDanio margaritatus was first “found” for the aquarium trade in August 2006 and was quickly described by Roberts[1] as Celestichthys margaritatus, which is where “celestial pearl” comes from. Apparently there was quite a hurry to get the first paper out as a few groups were trying to describe the species at the same time. It was only a year later that the species was moved to the genus Danio by Conway[2].

This unusual little fish was originally found near the town of Hopong, in the same area as the similar Danio erythromicron, but unlike D. erythromicron, which comes from Inle Lake, D. margaritatus is found in small, shallow ponds with a high amount of vegetation. Over the next few years, more collection points were discovered, including in more areas around Hopong and as far as Thailand[3].

The fish became so popular due to its small size that in a matter of months, large parts of the habitat where it was originally found had apparently been destroyed, which triggered a blanket ban on export, but the Danios proved easy to breed, so captive bred specimens were almost immediately available. The fish appears to retain its beautiful colour when bred in captivity, while wild caught specimens are difficult to feed, so one should aim to only buy captive bred fish. It would be irresponsible to continue encouraging the destruction of a habitat through purchasing wild caught specimens. A couple of the more positive side effects of this species becoming so popular was the increased income of the local fishermen, who were paid 20 times more per fish when selling to the aquarium trade than when selling the fish locally for food, and an increase in availability of other dwarf species, such as Boraras, in the aquarium trade.

The recorded SL was 21.2 mm for a holotype male and 20.5 mm for a paratype female. It is quite possible that the species may grow slightly larger, especially since the specimens I bought are already around 20 mm, while the breeder said that they would grow another 30%, so would reach around 28.6 mm. Unfortunately, I was not able to see the parent fish to confirm this.

The temperature, as recorded by the closest weather station, which is approximately 400 metres higher above sea level and 30 km away, ranges from an everage low of 8 °C to an average high of 29 °C. From this, I would assume that the water temperature that the fish are found in would be within 15 to 25 °C, which is in line with what the breeder I bought them from told me: he said that the fish showed best colouration at 20-22 °C, losing most of its brilliant colouration at 25-26 °C. I had already assumed as much, which is why I set the aquarium heater to 20 °C as soon as the cycle was complete. This way, the fish should show best colouration for most of the year, only losing it in the summer, when air temperatures reach 30-35 °C.

Due to its natural habitat, this species is most likely best suited for small, shallow and well planted aquaria with low current. 60 × 30 × 30 cm aquarium seems to be ideal for the species as males may fight in smaller aquaria, but the fish “get lost” in larger aquaria. The majority of the plants found in the area were from the Hydrocharitaceae family, although the fish seem content with anything which provides a thick cover.

This species is compatible with most other small, peaceful aquarium fish which prefer plants and a slow current. Most of the Asian species I list as suitable for 60 litre aquariums should be comptible.

The fish’s diet appears to consist mainly of small invertebrates, although they readily take dry foods. For best colour, it is advised that the fish are fed a varied diet, including a large proportion of tiny live foods such as newly hatched Artemia and small water fleas. Due to the small stomach which is appropriate for the size of the fish, I would recommend that this species is fed small amounts of food often, for example, at least twice per day, although I expect that they would do well without food for a few days when kept in planted aquaria.


[1] Roberts, Tyson R. (2007), “The “celestial pearl Danio”, a new genus and species of colourful minute cyprinid fish from Myanmar”. Raffles Bulletin of Zoology 55(1): 131-140
[2] Conway, Kevin W., Chen, W.-J., Mayden, R. L. (2008), “The “Celestial pearl danio” is a miniature Danio (s.s) (Ostariophysi: Cyprinidae): evidence from morphology and molecules”. Zootaxa 1686: 1–28
[3] I do not have access to this reference: Hary, C. (2007), “Celestichthys margaritatus: Perlhuhnbärblinge gibt es nicht nur in Burma” (“Celestichthys margaritatus: pearl chicken Danioninae are not only in Burma”). Die Aquarien- und Terrarien-zeitschrift, 60: 6–9

Picking up the Danios

After a lot of searching online and in local fish shops, and one failed attempt to buy the fish from a breeder in the next big city (Potsdam) because the breeder sold them to someone else instead of waiting a day for a reply from me, I found a listing on eBay Kleinanzeigen (a classified listing website). While not as close as my usual fish shop, the fish were only an hour away by public transport, door to door, which was an improvement on 55 km that I was thinking that I would have to travel to find the not-so-local local breeder that I had found through a forum for local fish keepers.

This breeder was only at home from 19:00, so I made an appointment to see the fish and, after becoming slightly lost looking for the entrance to the apartment block, found myself walking into a small lounge with three aquaria. The breeder asked me to sit by one of them and observe the fish inside, while he told me about how he looks after the Danios. The Danios were bold, well coloured and a healthy shape, with the females being full of eggs. In short, these were by far the best D. margaritatus I had ever seen. After 10 minutes or so, the breeder showed me the foods he uses, which were newly hatched Artemia, frozen water fleas and high-protein dry foods. He explained that the fish hatched in July, and were power fed (fed small quantities of high protein foods often) so that they were now 70% of their adult size.

After I confirmed that I was very happy with the fish, and he made sure that I had the details for his frozen foods supplier, he started catching out the fish into a bucket, while I observed his other aquariums. He had a lovely nano aquarium, which was suspended from the wall, containing a beautiful pair of young Badis badis, a planted 2 metre aquarium with Pterophyllum scalare and Paracheirodon axelrodi, and a rack of breeding aquariums, one of which contained Hemiramphidae (halfbeaks).

Once the breeder had the 10 Danios in a bucket, I counted them and he proceeded to transfer them to the fish bag that I had brought along. Since the journey was short and it was 20:00 by this time (so quite cold, around 5-10 °C), the fish were packed with 90% water and 10% air. Under normal conditions, for example form an fish shop or for long journeys, the fish would be packed with 10-25% water and the rest air, as the oxygen that is in the bag is all that the fish will have for breathing for the whole journey. Once the fish were double bagged, I paid the breeder and headed home.

The trip home took slightly longer than expected as one of the trams was late, but because of the unusually high volume of water and a few layers of bags between fish and air, the water did not chill much. I arrived home at around 21:00 and proceeded to drip acclimatise the fish, which took 3 hours. Unfortunately, I forgot to test the water parameters for the record, but I expect that the breeder has roughly the same water as me given that he pointed out that he uses tap water. Once the bucket was full, I transferred the 7 males and 3 females to the aquarium, topped it up with dechlorinated tap water and headed off to sleep.

Methods of acclimatisation

Since I had the tests out and I also had some spare test tubes, I decided to test the water which the fish were coming from:

  • KH: 6 ° (107 ppm)
  • GH: 16 (286 ppm)
  • ammonia: 0 ppm
  • nitrite: 0 ppm
  • nitrate: 20-80 ppm
  • pH: 8.0

As can be seen from the above results, the difference between that and the aquarium water is quite significant! If I was to move the fish straight over, they would probably get quite a shock from the difference in hardness, so I would need to acclimatise them first.

My preferred method of acclimatisation is often referred to as “drip acclimatisation”. The process is simple, although time consuming:

  1. I start by gently tipping the bag with the fish and LFS water into a bucket (8-10 litres for small fish, larger for larger fish), have something ready for covering the bucket as many fish are able to jump
  2. If the fish has been in transit for any significant period of time, or you have any other reason to suspect that there is ammonia in the water, add a product which temporarily converts ammonia into ammonium
  3. Add some décor and/or plants to make the fish feel more secure and relaxed
  4. Add a heater and airstone if needed, for example, if the air temperature is cooler than the aquarium water or if the fish have been in transit for a long time
  5. Next, set up an airline with a knot tied in it so that the flow can be controlled, to drip 4-10 drops of aquarium water into the LFS water per second for a 9 litre bucket (depending on how sensitive the fish are and the difference in water parameters: the smaller the difference, the faster the flow), for larger buckets, a faster flow should be used, for example, 10-20 drops per second for a 20 litre bucket so it takes approximately the same amount of time to fill
  6. Once the bucket is full, which usually takes 3-6 hours, remove the airline
  7. Transfer the fish from the bucket, into the display aquarium using a net, trying to minimise water transfer by not even dipping the net in the aquarium
  8. Disconnect all equipment that was used
  9. Throw away the water in the bucket (I water house plants with it)
  10. Disinfect all equipment used and throw away plants which were used during acclimatisation
  11. Top up the aquarium with dechlorinated water

The more common method involves floating the bag in the aquarium for a short period of time and occasionally adding large volumes of water to it: this does not particularly help the fish become accustomed to the new water and can be as harmful as not acclimatising at all. From what I have seen, this is one of the most common reasons, after ammonia poisoning, for deaths in new fish.

Importance of acclimatisation

Fish are osmoregulators, which means that they regulate the water levels inside their bodies by means of a process called osmoregulation to keep the salt concentrations inside their body constant, regardless of the fluctuations of salt outside their bodies. The process differs in freshwater fish and marine fish because of the environment, I will write about the freshwater process as that is what concerns this aquarium.

Some species of fish, such as some Poecilia spp., are able to tolerate a very wide range of salt concentrations in water, all the way from fresh to marine water: these fish are called euryhaline. But most (common freshwater aquarium) fish are not able to tolerate changes in salinity: they are referred to as stenohaline.

Water hardness is made up of metal ions and carbonates, both of which form salts, so harder water contains more salts than soft water. This means that it takes more work for fish to maintain body salt concentrations in softer water and less in harder water: keeping hard water fish in soft water can affect their health as they would constantly be putting more effort than is usual into maintaining their bodily functions.

Most fish have a blood salt concentration of 9 ppt, while fresh water has a salt concentration of under 0.5 ppt, so freshwater fish tend to try to maintain salt concentrations in their blood at higher levels than the water is at, which is achieved by ion intake through food and gills and by excretion of excess water by means of a dilute urine.

Most fish are not able to instantly adapt between different water hardnesses, which is why moving a fish from one water type to another quickly can result in death or serious injury. To avoid problems, it is important to acclimatise the fish to the new water parameters over a long period of time and with only small changes in the water parameters. In theory, if the start and end water hardness, pH and temperature are same or very similar, acclimatisation can be skipped.

Long term exposure to water types the fish are not suitable for cause increased susceptibility to diseases, because of the extra work that hard water fish have to do in soft water and because many diseases do not do as well in soft water, so soft water fish are not always as able to resist them.

Deciding on fish numbers

Most aquarium fish can be classed into one of three living preferences:

Schooling and shoaling:
These fish, depending on the species, live in groups that range form a few hundred to a few million individuals. Home aquariums are most often not able to hold groups that large, but the bigger the group the better it is. I usually recommend that one should aim to keep 10 – 15+ individuals per schooling species as there is no excuse to not do so if stocking a new aquarium. Unfortunately, some people find out that they have only a few individuals from a schooling species after the aquarium is fully stocked, in which case it is best to try and increase the numbers to at least 6 individuals per species or to find them a new home. In some way, fish are aware of individuals up to a point, at which the individuals become “many”. I think that 6 individuals is this point for many species. One of the most important functions of schooling is to protect the individual fish from predators, either by letting the weaker fish in the group be picked off first (as easier prey) or appearing as one larger fish. The main difference between schooling and shoaling fish is that shoaling fish will normally only swim in a tight formation when threatened, usually going about their own business (for example, Trigonostigma heteromorpha). On the other hand, schooling fish (such as Paracheirodon innesi) will spend most of their time swimming close together, even to the point of facing the same way. The group includes fish like tetras, rasboras, danios, barbs, many loaches and rainbows. One unusual member of this group is Neolamprologus brichardi, a shoaling cichlid.
Small groups:
There are a few different variations of small groups which can be found. These include small groups of social fish, which do not have much social structure (such as livebearers) or which have a specific social structure (for example, cichlids); closely knit family groups; pairs of breeding male and female couples; harem groups of one male and a number of females (often seen in many Apistogramma species), or quite rarely, one female with some males. As with schooling fish, small groups provide security for individuals. For some mildly aggressive species, such as Pterophyllum scalare, it may even be possible to keep them peacefully only individually, in proven breeding pairs or in small groups of more than 6 individuals because the dominant fish can then spread the aggression over multiple individuals, instead concentrate it on a single one.
Solitary:
Some of these fish are too aggressive to keep with any others of their own kind, and in some cases, even with other fish which would occupy the same area inside the aquarium, while others simply do not interact with one another on a regular basis. This group includes some loaches, cichlids and gouramis.

It is quite important to try and keep the fish in appropriately sized groups as some may otherwise display odd or aggressive behaviour. The easiest way to find out appropriate stocking numbers is to research the conditions in which the species is found in the wild.

Some basic research showed me that Danio margaritatus and Yunnanilus sp. ‘rosy’ is a peaceful, mid-water schooling fish, which automatically means that I should be considering 10 individuals per species. This is a good number to start with, and there is always the option of adding more later.

Pseudosphromenus dayi, on the other hand, is a solitary fish which breeds in pairs. Males may occasionally be persistent, so I decided that it is better to have 1 male and 2 females, to give the females a bit of a break in case of uninvited attention.

So for my first “final stocking”, I will be aiming at the following:

  • 10 × D. margaritatus
  • 3 (1m 2f) × P. dayi
  • 10 × Y. sp. ‘rosy’

It is very common for final stock to evolve with time, which is why I am referring to this as my first one. As for how I decided on the total number of fish? That is rather difficult to explain as there are no set rules, nor have I seen any good guidelines. I chose the number based on my experience and I always base my decisions on adult size. The stocking numbers are also affected by the amount of plants in the aquarium as they will use up ammonium. For an aquarium which is 60 × 30 × 30 cm in size, I would normally expect to stock between 6 individuals of the larger species I list and 25 individuals of the smaller species. I would also stock conservatively if I pick female livebearers because they will drop fry and it is best to reduce chances of overstocking.

The best advice I can offer on stocking is to not stock more than one feels comfortable with, even if others say that the aquarium will take more fish, and if one is being advised to stock less than one plans to, to try the lower stock first.

Daily tests: days 39 – 47

Filter is still steadily processing 2 ppm of ammonia in 24 hours. The Danio margaritatus have gone on hold because the breeder I was planning to buy them from sold their current batch to someone else, so I will move my Pseudosphromenus dayi into the aquarium first.

60_litre_asian_v8In preparation for the fish, I have just ordered the remaining plants, including some impulse purchases, and I have also ordered a piece of “red moor wood”, which does not look particularly red but will provide a good place for the new moss to grow on. The moss is Vesicularia ferriei, which is known by the name of “weeping moss” because it grows sideways and downwards, which I think will look good on the wood. For the moment, I have tied it to porous rocks, which were used as ballast in the Lindernia rotundifolia pots, with some black cotton thread. Cotton thread will eventually rot away, which is not a problem as the moss should have grown into the rocks by then. Alternatively, nylon string or fishing line can be used as these do not rot in water, but these can be dangerous to fish if they are loose because fish can become tangled the string and can cut themselves.

Plants layed out

In preparation for the new plants and fish, I have also replanted the Lindernia rotundifolia, so that the tallest plants are at the back and the shortest are at the front. The plants now form a very rough hemisphere. I am not so sure about the (apparently) general consensus that these plants as fast growing because they are yet to show that quality to me. So far, growth has been moderate at best, but steady and healthy… I will have to try measuring the growth rate at some point in the near future.

Picking species…

So, I was a little impatient and started looking for plant and fish stock… and of course, I grabbed the plants when I saw them (also made arrangements for more species in a few weeks) which means I should spill my ideas about now. I will be using mainly scientific names because many fish have various common names associated with them and some are common between different species.

Various fish species prefer different areas of the aquarium, so unless one is careful about filling all the levels, soma parts of the aquarium may end up being completely empty, while the fish concentrate in others. There are three main levels to consider:

Surface:
These are fish which either spend much of their time at the surface because they are surface feeders or breath through labyrinth organs. Most common of these are gouramis, Bettas, hatchetfish and some killifish. These fish often have superior mouths.
Mid-water:
Mid-water schooling fish are most common, they are usually found in groups of a few hundred to many thousands, in the wild, which is why they do best if kept in groups of 6 or more, but even better in groups of 10 – 20 or more. Some examples of schooling fish are barbs, danios, rasboras and tetras. Other mid-water fish also include many livebearers and cichlids. These fish usually have anterior mouths.
Bottom and surfaces:
These fish are often grouped together, but make up two quite distinct groups: fish which live towards the bottom of the aquarium and those which live on surfaces and the bottom itself. The first group include earth eating cichlids, some loaches and some Corydoras, while the latter consists mainly of plecos, shrimp, the remaining loaches and Corydoras. The large majority of these have inferior mouths, although some do have anterior ones.

Because the aquarium is only 60 by 30 cm, it restricts me to only the smallest species, as I want my fish to have enough space to turn around and interact with their environment. So, I am restricted to about 30 mm for active schooling fish and 50-75 mm for fish which have low levels of activity. I am going to go for the standard configuration: one group of schooling fish, one group of “bottom feeders” and a couple of centrepiece fish.

First, I need to decide on which fish I wish to focus. As I have not kept loaches in the last five years, they are one of the species I want to look at. Also, living in Germany, has given me access to many unusual species, such as Boraras, so this is starting to look like an Asian themed aquarium. Asian leads me to thinking about gouramis and Bettas, my LFS currently had some Betta channoides, B. strohi, Parosphromenus deissneri, Pseudosphromenus cupanus and P. dayi. So I do a search of all these species, first on Fishbase then read the first ten search results for each, as the internet is not exactly renowned for the accuracy of all information. Average results show me that all species are suitable. I already happen to have a pair of Pseudosphromenus dayi, so they’re going to fill my “centre piece” and “surface feeders” slots.

Now, that leaves me with need for a “bottom feeder” and a “mid-water schooling” species. I start searching through Planet Catfish for small catfish and find Erethistes jerdoni and Erethistes maesotensis, from some experience and conflicting search results, I know that Erethistes and Hara are used interchangeably. I haven’t decided if I really want to go for catfish and loaches, so I’ll just keep these in mind for now.

So now I start looking at loaches, for which, unfortunately, there is no good species resource like Planet Catfish, and come across Yunnanilus cruciatus and an unidentified Y. sp. ‘rosy’ (also known as “Tuberoschistura arakanensis”). After some more searching and enquiries, I decide that Y. cruciatus is on the too large side, and Y. sp. ‘rosy’ is about right. Both of these small loaches are schooling fish, and tend to swim mid-water.

Last, but not least, I looked at the schooling fish.. I was originally planning to go for a Boraras species, but I discovered that Danio margaritatus are from the same location as Y. sp. ‘rosy’. I generally prefer to aim for biotope or at least the same continent or water type, and I have been wanting to keep D. margaritatus for many years now. When this species was first discovered, their habitat was almost destroyed by the greed of fishkeepers everywhere, and the wholesalers falling over themselves trying to collect the species. It has now been a few years, but I will still not buy these fish if they were wild caught, so I am now searching for captive bred specimens. I would also like to mention another interesting species of the same size is Danio erythromicron, it is also very unusual, but an excellent find for a small aquarium.

I will continue with numbers of each species, stocking order and plants in the near future…