Amazon Puffer (Colomesus asellus)

The Amazon Puffer is a small, colorful, fast-moving species that is very active and full of personality!

The Amazon Puffer (Colomesus asellus) is widely considered a holy grail freshwater puffer species that is native to oxygen rich areas of the Amazon Basin. It sometimes lives in loose groups and grows to an adult size 3 inches in captivity, yet the largest wild specimen was measured at 5 inches. Like many pufferfish, it is very active and has plenty of personality. This particular species is not as aggressive as many other freshwater puffers, and many hobbyists keep this species in a communal tank. Its body shape is designed for navigating fast-flowing waterways, making it much more agile than most pufferfish.

One major key to successfully keeping the Amazon Puffer in a community setting is ample space and décor. Slower moving tankmates with long fins should avoided as they may get nipped. Males of this species can be particularly territorial and will often claim and defend an area, so more plants, rocks, and driftwood will help to break lines of sight and create more distinct spaces. It is ideal to stock this species with a quantity of either 1, or a group of 6 or more as less dominant specimens may get picked on in smaller groups. Since it is native to fast-flowing, oxygen rich rivers, it is particularly intolerant of subpar water quality. Regular water changes are an absolute requirement for this species. Also, a full volume turnover of 6-10 times per hour is necessary for any aquarium housing the Amazon Puffer.

Dry foods are often ignored by the Amazon Puffer, although sometimes groups of this fish will learn about new food sources by watching one another try them out. In our experience, it is not a good idea to rely on dry foods as a staple for this fish. It will, however, eat frozen bloodworms and other meaty frozen foods.  Its wild diet mostly consists of crustaceans and snails, so it should not be kept with dwarf shrimp or other ornamental invertebrates. On a positive note, it will happily clear any aquarium of any small snails, including the “nuisance” bladder snails that inhabit most planted tanks. Like most pufferfish species, its beak needs worn down through regular feeding of invertebrates whose shells are still intact. If the beak is not worn down through a diet of crustaceans and snails, it can quickly become overgrown to the point of affecting the fish's ability to eat, eventually requiring you to manually trim it.