Glass Fish: A Quick Overview
The dwarf glassfish (Gymnochanda Ploegi) is a relatively new and very underrated fish discovered in 2014 in the Sanggau and Kapuas Lakes regions in West Kalimantan, a part of Borneo belonging to Indonesia. It took collectors over 3 hours to trek to their home site which consists of tannin stained, stillwater pools near swamps and rivers. It’s named in memory of Alex Ploeg, a taxonomist, advisor and conservationist against alien species for contributions to the ornamental fish trade and role as Secretary General of Ornamental Fish International; who sadly perished in a tragic accident over Ukraine in 2014.
All dwarf glassfish are scaleless as well as see through. This adaptation to avoid predation by simply being less visible also allows us to see all the fish’s internal organs, digestive tract and spine, a very unique attribute. Unfortunately, this has also lent to the species, particularly P. Ranga, being forcefully dyed with a fluorescent solution so they can be sold as “glofish”. Those fish that survive the injection process are highly susceptible to bacterial and viral infections and are in such a weakened state by the time they arrive in the stores that they generally only live for a few weeks. This practice has been widely condemned and reputable retailers won’t carry these fish.
A big draw to the Ploegi specifically is the surprising dichromatism and sexual dimorphism this species presents. Males will have extended maroon tinged anal and dorsal fins and both males and females have a slight yellow sheen and light, vertical black banding on their bodies. Much like most other species of glassfish, the Ploegi are very peaceful and retiring. They will not only easily be outcompeted for food, but will most likely constantly hide if kept with any fish other than those that match their very shy and timid nature. We’ve personally found a good combo to be Microctenopoma Ansorgii; a small west african anabantid; corydoras and Neocaridina shrimp. However, they will do very well in a species only tank if you’re willing and/or able to provide one.
Care isn’t too difficult, but there’s long been a myth that they are difficult to keep alive in captivity due to the fact that they require brackish water to thrive. This is simply not true as they mostly come from stillwater pools and slow moving freshwater mountain streams, not brackish estuaries. They can acclimate to be kept in both fresh and brackish settings, but either way, consistency is extremely important. Temperatures can range from 70-82 degrees and pH from 5.0-7.0, but they do like their water a little softer and more acidic, if that can be consistently provided. They’ll only get to be around 1.5 inches so a 29 gallon would be sufficient for a group of up to 20 individuals but they’ll appreciate more space for larger groups. It’s suggested that the minimum to keep is around 10, but as with all schooling or shoaling species the more you keep the more you’ll see their true behaviors come out, which is very enjoyable especially for this very curious and playful fish.
There haven't been many successful breeding attempts, but this is most likely due to the fact that this is a newer and less commonly kept species in comparison to other types of glassfish. They’re egg scatterers and plant spawners so it would be best to keep them in a fairly heavily planted tank. Not only will the plant cover help to balance your tank, it will give the glassfish more confidence and give you the best shot at spawning should this be your goal. Water changes and temperature increases to around 84-85 degrees should also help to induce spawning behavior.
Overall this is a beautiful, curious and peaceful fish that makes for a stunning species only tank or an excellent addition to a very calm and peaceful tank. Despite their rarity in the hobby and geographically challenged locale, they remain a very reasonable price ranging from $8.99- $12.99 a fish. Hopefully we get some more hobbyists breeding them in the near future so we see them a lot more.
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