He's gonna gain weight REALLY quick if he's been starved as long as we suspect. There was a study done not too long ago covering this for the people who do aquaculture. What they found was that if you feed your control group and your test group the same for three months, they'd grow the same. Then they'd continue to feed the control group as they were before but they starved the test group. As you'd expect, the control group grew faster than the test group. The surprise came when they started to feed the test group again: they grew much faster than the control group and eventually caught up in size to the control group, at which point they slowed down to match the growth rate.
Fish metabolisms are a fascinating thing.
Just for S&G, here's my boy, Billy Badass. He had a very hard time getting to eat anything other than live fish as well, with two near- death starvation periods. I got him on pellets just before I moved, but since I moved he refused to eat pellets again. After another month long starvation period, he started eating worms again. After a couple of weeks, he's still very thin, but he's starting to put on weight again. I love brevis, IMO they're the most badass looking tigerfish. Billy's about 6" or so.
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