1. Bleach is fine, let it air out for 1-2 days. You probably won't be adding fish the same day as you clean it so it should not be a problem. You'll probably also cycle the tank for 24-48 hours as well which will help. If you really don't want to use bleach, go with something mild like Simple Green or Dawn.

2. Filtration and heat should be for at least 1 tank size larger than you have. So filtration and a heater for miniumum of a 55gal tank should suffice. As a rule of thumb "you can never have too much filtration" so if it fits, go with the equvilant for a 75gal tank but that's how I would do it.

*3. I've seen fish live together that "shouldn't be able to", particularly angels, tiger barbs, and neons. Some how they lived together. A 40br tank is a good size to house fish together given the proper "hiding" places and "territories. So you may get away with a couple angels and tetras or whatnot. I've never kept angels cause I heard they can be sensitive to things so and I always hear how people mix them with fish which normally woldn't survive around them. Can't help you with discus, but bala sharks may work out.

*4. I've heard different plants require different lighting and different fish will eat different plants. Did you follow that? ;-) So meshing the right fish with the right plants and the right lighting and possibley the right substrate are all to evaluate in your process.

5. I always suggest African Cichlids for a fish tank as they are "pretty" and almost make you want to get a saltwater tank. They are also interesting fish to watch socialize with each other. They are also a preference of mine as well.


*If no one else chimes in(I think Expensive Hobby could really help you out here), I'd look for a fish forum or a store in your area which is an actual "FISH STORE", unless you know the guy at Petco(or other pet store) who actually is a fish hobbyist who could walk you through it. Hope what I've said helps a little as I'm not as advanced as it looks like you are going. Good luck and send pics when all is set up.