There's a LOT no one tells you and unfortunately fish tend to die b/c no one says it. Eartheater ciclids are jackass fish, big pig eaters and bullies of gentle fish like peacock gobies. The two of them divided up 55 gallons amungst themsevles; this is your half...
NOTHING gets along with freakin' Bettas, and EVERY fish book and magazine I have says, oh, you can put them with other fish...they either eat (ie guppies) or will get picked on because they're slow swimmers and bright with bushy tails. Just go buy the Eclipse 3 gallon from Dr.s Foster and Smith online (best price, fast service) and keep him alone with some nice java ferns, hornwort or dracena varieties and a therm and 25 watt heater (the smaller, flat ones are useless). Unlike you see at the store, they're VERY active in the GREAT three gallons. They do well in a place you spend a lot of time, like the kitchen. They seem to interact with you unlike many other fish. The Eclipse has a great-fitting lid, and when you get it broke in a bit, it hinges with a little practice just like the door on a big tank.
A kid I know never puts dechlorinated water in with his guppies, just lets the water sit overnight, and he has the most gorgeous guppies I have ever seen. They don't look a bit worn at the top of their head and shoulders like they tend to look.
Guppies are great, fun, underrated fish.
Save your money as far as big snails and shrimp are concerned. Big snails are inactive, worthless cleaners, and they don't live very long. Neither do shrimp and you never see them, either. I prefer small snails, myself. Yes, the same ones everyone hates. They make the plants clean and they're fun to watch. The ciclids eat them if there are too many.
Had I known, I would have BEGGED the fish store (specialty store NOT chain store, one you KNOW had clean tanks, with healthy fish) for used filter elements, and aged "top water" from the top of the tank. I can get a tank moving with aged water and used filter elements and a few live plants in a few days, easy. I lost three fish trying to break in a tank without them. and it was horrible to watch, as you want to dump chemicals all over them, which normally doesn't help.
I wish I had ignored all the books that said how "community" eartheater ciclids and dwarf gouarmis are. NOT TRUE. They both bully everyone they can get away with. The swordtails are sizable and tough, but the peacock gobies will have to be moved to another tank, as they have they grey circles on them that I was told indicate bullying (from the gouramis, as they're new).
Both gouramis and ciclids pick at the bottom of "baby fry cribs," so if you have fish that would sit on the bottom of the net, they'll get severely injured, if not killed. I lost two that way. Fry are smarter than you'd think, as they tend to hang out near the fry cribs, and wait until I see them.
I found it's easier to lower the net,) keeping your fingers where it scares the others so they don't swim to the opening), and kind of coax them into it; as they know that's where all their siblings are and that's a safe spot. It's NOT easy to grab fry with a fishnet, as they jump out when you have to lower it to get it out of the tank. If that don't work, or they're behind the heater, suck them up with a "tank only use" turkey baster. Squeeze the bulb, stick it in the water (the bubbles will spook the fry), and suck them up. It's better than having the fish eat them, which isn't healthy for the fish OR the fry--too much bacteria possible.
I wish someone told me antibacterial meds don't normally work, and kill off your good bacteria. The ick meds only work if you get to them at the first spot.
I wish somene told me to hang onto a semi-used filter element with the carbon cut out b/c cutting out carbon for illness treatment is messy.
Someone should have said, always buy more gravel than you think you'll need.
Fish are individuals, and deciding they'll get along or not based on a huge group isn't quite right.
Bettas in Chicago water (8.0 ph out of the tap) are greatly helped with Dr. Attison's Betta SPA. A small amount of maybe 7 ml for three gallons at water changes and you don't have to do anything else to you chemical levels minus change the 20% of the water often. I wouldn;t like to get into too many Ph screwing around type chemicals as they hurt the environment, and require maintinance of the chemicals. Attison's is all natural, and I have three Betta, and I can say it works. It binds to the bad chemicals, which you can see as a brown dust on the gravel.
Someone should say that the fish you'll love is entirely impractical for a tank. I love the silver cats, but at up to 36 inches long, who can support that? I also love green saddle wrasses, but I am freahwater, of course, and spend enough on fish as it is.
Someone should tell you that the lidless bowls and tanks are stupid, as Betta can certainly jump out. Good thing they can breathe air for a bit. I almost had a stroke when I touched him b/c I thought be was dead, and he flipped! Also, the coffee table tanks and tv style tanks are also mean, stupid, and shouldn't be used. The tv ones are cruelly narrow, and the coffeetable ones are a pain to get into AND they're at constant risk of getting banged into by everything.