I have 2 bichirs in my 75g, one is a Delhezi and another is a Palmas. The Delhezi was in the tank for about a month longer than the Palmas, the Palmas when I bought it was much smaller than the Delhezi. However, in the last 4 months the Delhezi has not grown much, but the Palmas is now larger than the Delhezi. The Delhezi is about 4 inches long and at most grew about an inch and the Palmas about 7 inches long. Both are fed massivore pellets and I see both eat about the same amount so I know it isn't that one is being outcompeted for food. Is this normal or something bad?