Most people often mistaken this fish species simply as a shark which lives in the sea but in actual fact, it is not true because red-tailed black shark is a freshwater fish. It shares few similar characteristics like a clown loach, first because it is a bottom dweller and other reasons are because the shapes between both species look very much similar. Perhaps what makes the red-tailed unique is that, it has a complete black coloration covering its body except for the tail fin, which appears as either orange to red coloration. Similar like clown loach, it also has barbel near the mouth region.
Trying to find suitable tank mates for your red-tailed shark is a difficult task. Since it does not mix along well with most common community fish because of its territorial behavior, aquarist only keep this fish in its own tank. Even among the same species, they could live together with each other when they are young, but once a dominant fish outgrows the rest, it will end up harassing the smaller ones. A mature red-tailed black shark will also define and protect its own territory and will chase after other fish that encroach into its area. In fact, trying to mix them into an established community aquarium will actually resulted in complete havoc. So the answer to a simple question on whether two red-tailed black sharks could live together in the same tank is definitely, no.
Luckily, there are options available with a small number of fish species that could be tolerant of its behavior like tiger barbs while there are different opinions regarding convict cichlids as potential tank mates. So far I’ve also tried before mixing with platy but once it grew larger than the pack, the harassment nature starts to kick in. But one thing for sure, I would avoid mixing them with pleco and clown loach because both species are also bottom dwellers in which they will clash with your red-tailed while scouring for food. Although the red-tailed black shark doesn’t really bite and injure other fish, it loves to chase them around and most of the time will drive the other fish into hiding and will never let them out. If you are planning to house them together with other fish species, I would suggest getting even larger aquarium, more than the standard recommended size of 55 gallon and provide a lot of hiding places.
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