I have four synodontis Euruptus (featherfin syno) in my main 75g tank. They seem to get bolder as they get larger, three of them are about 4-5 inches and one about 2.5-3. They get to about 6-7 inches I believe.
The smaller one is very reclusive apart from feeding time, while the other three jostle for a space in the middle of the tank with a bogwood branch to hang under, but also happily sit out in the open frequently. There are a number of smaller fish in this tank though so maybe that helps them feel at ease.
Very interesting fish to watch gliding around the tank, and they more than hold their own even when other fish are breeding from my sig.
Also swim right to the top at feeding time sometimes.
good luck if you get some, they can be quite pricey so if you can get them cheap i think they are worth it. How much are you getting them for??
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