Originally Posted by firearies
I've heard two diff. stories on red tailed black sharks. Keep only one and they won't get aggressive, or keep them in schools of six or more. They will mess with each other leaving the other fish alone, like tiger barbs.
this has been my experience. Red Tails are my fav fish. I've kept them for many years until about a year ago when I moved cross country, and I plan on getting them again.
Like most fish, they are individuals. Some are more aggressive than others and cannot be kept with more delicate fish. The "One or several" rule for ret tails is also generally accurate. But again, the rare individual will challenge that rule.
The biggest factor in these fishes behavior is their tank size. Anything smaller than 55g and you'll see a fiestier fish. And 55g is a definate minimum. I'd suggest larger. I kept a single Red tail in a tank with a betta and school of 12 tiger barbs in 55g and everyone got along slendidly.
Red Tails are territorial and REQUIRE somekind of hiding structure. Be sure to make it large enough to accomadate their adult size, 4-6 inch. Here's another myth I busted first hand. Red tails DO get larger than 4 inches and can reach 6 inches long. Make their cave large enough for them.
If you have a particularly aggressive Red Tail and decide you just can't bail on him then frequently moving that cave hide-away will help keep his aggression down. If done too often though you will tend to stress the fish so I'd suggest moving these more aggressive fish to a chiclid tank where they'll feel quite at home.
Also, these fish are jumpers! If you're using aqua clear expect these guys to jump up the water fall and chill in the filter for a while. Make sure the cover on your aquarium is tight and has no other holes for the fish to jump through.
These fish are awesome and though they may be a bit more complicated for a beginner, I highly reccomend them.