Rainbow sharks

Maybe for a very little while. As they mature and get older they will become very territorial. You will not believ the wounds they can inflict on each other. Besides which they would get rather large for that size tank. You are talking about a fish that gets up to 15 cm or 6"s. Five six inch fish in that small a tank would be overcrowded. IMO. I have never been able to keep more then one rainbow shark to a tank over the long haul. I have tried many times as my son loves them and it never works for the long haul.
 
I agree with Darkangel. My 5" RTBS is quite bossy with even the smaller fish in my 72 gallon tank. It particularly does not like the smaller loaches for some reason. I have seen young rainbow and albino sharks together but once they are older, look out!
 
I agree, I had 2 in a 55 gallon a few years back, they seemed to get along great until they got bit larger....maybe about 4" or 5". Then ll he** broke loose. Each "owned" 1 half of the tank. If one came remotely near the mid-line, the other came out charging. Eventually, I noticed one had a big chunk bitten out the side. The next day, the other had one too..... before long, both of them had fought until they were both too weak to carry on....... I advise against it...... I learned that if I wanted to venture the RTS avenue again, it could only be one to a tank at the most.....
 
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