Sunfish compatibility?

I have now a Coppernose bluegill and a Spotted Sunfish. Are these two going to be compatible with each other? From what I have read it seems the Coppernose will outgrow the 46 gallon tank I have for them. It is currently about inches and the Spotted is about 3 inches. I have the Spotted houses in a 20 high for the moment but plan on introducing the 2 today unless someone advises me otherwise.
If the Coppernose will grow too large I will look into catching another sunfish or two. Can anyone refer me to a site or a thread here listing their captive husbandry requirements? Do Sunfish school? Should I try for a school of 6 or so individuals? My filtration is good, so a bit of overcrowding isn't a problem if it will contribute to the health of the fish. Thanks.

Here's a digest of what I've learned about sunnies from my limited experience keeping them (I've kept Green Sunfish and Warmouth, two of the larger species) and the gracious assistance of the more experienced keepers here at NANFA:

Sunfish don't school, and they tend to be territorial; if you want to include more than one, be sure to include plenty of cover (driftwood, plants, flowerpots, pipes, etc.) and use it to divide the tank up into sections. Keep catching sunfish and you'll likely come across some more of the smaller species that would be better tankmates for your Spotted than that Bluegill will be; I'm not sure which ones you have in Florida, but other Lepomis such as Dollar, Orange-spotted, and Bantam Sunfish are similar in size to Spotteds, as are Fliers (Centrarchus macropterus) and Banded, Bluespotted, and Black-banded Sunfish (Enneacanthus sp.); these guys all stay in the 3-6" range. There are plenty of other native fish that are compatible with sunfish, provided they are too big to fit in the sunnies' mouths.

They're pretty hardy fish; you don't have to fret too much about pH, hardness, temperature, and so on. Sunnies are predators on smaller fish and inverts, but you can train them to pellets. Most of them are gravel nesters; if you see a male sweeping off a circle of gravel with his tail and acting more-than-usually aggressive, you'll know he's ready to spawn.

My experience with sunfishes is somewhat different. As larvae and fry in large tanks (> 200 gallons) several species including the bluegills, redear and green sunfish do move as a school with many thousands to even tens of thousands moving a single cohesive group. As juveniles they break up into loose shoals that do not maintain their integrety throughout day. Juveniles of bluegill in my tanks will alsoo set up feeding territories when a food source is defendable and worth the effort. Not all within a brood will engage in territorality and size not the most importnat factor with that. Adult females of the spotted, red spotted and central longear sunfishes will also move about foraging together in groups of 2 to 5 for hours within some streams I have watched.

I keep spotted and coppernose bluegill together frequently. Usually a small number of spotted and and larger number of larger bluegill. Just watch out for your spotted if he feels the need to breed and the bluegill is not willing to fight back. Most of the these arrangements are in 75 gallon tanks but I have kept such mixtures in 20 gallon tanks.

Centrarchid is the expert here- if he disagrees with me, it's because I'm wrong!

Still, I don't think sunfish need to be in schools to thrive, the way many minnows or characins do. Your spotted will be fine with or without company. I think your Bluegill, when full-grown, might be cramped in a 46 gallon, especially if you have several other sunfish in there.

Centrarchid is the expert here- if he disagrees with me, it's because I'm wrong!

Still, I don't think sunfish need to be in schools to thrive, the way many minnows or characins do. Your spotted will be fine with or without company. I think your Bluegill, when full-grown, might be cramped in a 46 gallon, especially if you have several other sunfish in there.

I would like a multi-species tank, so I'll have to scrap the bluegill and try to find a few smaller, compatible fishes for this tank. It will be heavily planted with several territories broken up by driftwood and slate rock. Any compatible tank-mates for Sunfish? I'm assuming some smaller plecs would be fine. I would agree that the schooling/ shoaling behavior is probably not something to worry about, but I would like to breed a pair. Do they pair off? Harems? Any recommendations for other native fish that would compliment a pair of Spotted Sunfish?

Another sunfish that you can probably find in florida and are not as large as the bluegill would be the dollar sunfish (Lepomis marginatus). I breed a lot of sunfish and I typically keep groups of 6 (when I can get them) in 55 gallon tanks with 4 females and 2 males. I would think you could do this in your 46 as well. If you want the tank to be just a variety of species I would set it up with one male of multiple Lepomis sp. rather than a breeding group. Sunfish will try to breed in multi species tanks but the aggression of nest defending males can be a problem. Another tactic that works well with sunfish (if you just want to display them) is to overstock to the point of them not having the space to set up individual territories. I know this is also done with cichlids and can work well if you are willing to keep up with the maintenance of a high bioload in the tank. Newt mentioned several other species that stay small but some of those are much less aggressive than spotteds and would not fair well in the same tank. I would not mix Lepomis sp. and Enneacanthus sp. in the same tank except in a few special cases. The three E. species are the smallest sunfish and also much more dossile, most of the time they do not get larger than 2-3" in size. The smallest and least aggressive Lepomis are Orangespotted and Bantam Sunfish. The Bantams can hold their own with spotted of similar size but orangespotteds do not compete well with the more aggressive Lepomis sp. If you have any other questions about specific species feel free to ask.