I've kept istlanums, have had grammodes but not long term, what do you want to know?
Both species get to about 12" eventually, very slow growers though. Both are
very aggressive, at least adult males are (but I have heard of nasty females as well)
Both species are very shy as juveniles and will hide most of the day. This changes after the fish is mature, I'd say 6"+, they become outgoing.
The istlanums come in a red and green morph, the care for them is the same, same fish different colors.
Here are some of my istlanums. Bigger green guy I had years back, probably about 7-8". Smaller red I was growing out last year but re-homed due to a move. This is one of my favorite species for sure.
