I dont think its normal for gourami's to lay at the bottom of the tank. Gouramis are labyrinth fish which breathe from the surface and tend to stay near the surface most of the time.
I think they do it periodically, so if it's an occasional thing, and there's still a good level of activity, swimming, and searching for food and breathing from the surface, it's fine. I would say if the gourami isn't sleeping, and it's doing for say, longer than a half hour, a water test/change might be in order.
My gouramis only sit at the bottom if they are really stressed or ill. As legendaryfrog said, they are labyrinth fish and breath air from the surface, so that is where they usually remain, unless there is something wrong with him.
If have a gourami who is sitting at the bottom that is usually not normal. Is he clamped at all? How long does he sit on the bottom? He may be stressed, uncomfortable or something else.
Mine are all over the place too. They never stay near the top in particular. They seem healthy, always searching, good exercise. I would'nt think that remaining at the bottom is healthy behavior.
I just got my first gourami about a week ago (dwarf), and he is all over the place too. He is often near the bottom, poking around in the gravel or at the base of plants but he never stays there long.
OK, I'm going to treat mine for intestinal parasites. Lately three of them have showed a marked decrease in activity, including resting for long periods (10-15 minutes) on the bottom.
Three of them have shown abnormal poo... white, stringy, mucosy.. all that yummy stuff.
I'm going to try to order some Paracide-D from fishypharmacy and/or try to get something from Petsmart (shudder) tomorrow.
Thanks guys. It wasn't the resting on the bottom that concerned me as much as the sudden shift in behavior especially from the dominant male.
What kind of gouramis are they? If they are dwarf gouramis, they are usually very suseptable to internal parasites because of the way they are bred (I don't know much about this, but I know its true) but yeah, white stringy poop and sitting on the bottom is almost a definate sign of internal parasites with gouramis. Good luck, and I hope your fish get better.