You can't get a grouper in your 15 gallon tank. But, if you want a bigger tank, groupers eat meat, frozen or live, they aren't shy. My strawberry grouper was so mean it was scary to his tankmates, but now hes at our lfs. :)
A nice tang, or angel would do nice, but come of those fish may get to big. So, you'd hafe to get a bigger fish, or get rid of your fish, when it grows up.
I saw some niger triggers that size in my lfs. They are usually nice, but some people on this bb got some bad apples, and yes they are extremely hardy.
Goober, I have the same problem as you now. My readings are all perfect, and red algae. I do now about water changes every 3 days, to get rid of that stupid red algae. Any ideas of how to get rid of it?
I've heard blue lined triggers and queens are extremely mean just like undulateds, so I guess you might, but the triggers would hafe to be about 4 in. or 4.5 in. But it's a little risky because undulateds are extremely mean.
Ya, they did have them before.... But if you want to come out by my way, theres a store called scott's pet shop, Great store with rare fish, they have saltwater plants. If you want to know the exact place just ask.