So, I wanted to wright a compatibility guide. I will list the fish that are safe (or not safe) and put special needs, tank size, etc.... Let's Begin:
Snails- Research different species, if they eat plants, and if they can become aggresive before buying. Tank size: 1 gallon +
Corydoras Catfish: Need to be kept in groups of 4+, and need a soft substrate that will not damage their barbels. They are very sensitive to salt and meds, so be careful. Tank size: 10 gallon +
Bristlenose Pleco: Needs driftwood to be healthy. If put in a tank of ten gallons alllow lots of driftwood, rocks, etc for the pleco, as this increases the amount of space they have for feeding and exploring. The albino variety is generally smaller. Tank size: 10 gallons +
Kuhli loaches: Require sand or soil to dig in. Must be kept in groups of 3+. Sensitive to salt and medications. Tank size: 10 gallons+
Common Guppies: Need to be kept in groups of three plus. Will breed out of control in mixed gender group. Tank size: 5 gallons (Not recommended)
Most bottom dwelling or non-colorful fish will be okay with bettas. This is just a general list of commonly found fish
*These are not guarenteed success, overly agressive fish may attack, although it is uncommon.
Neon Tetras- Need schools of 4 or more, 6+ is better. Bright colors may provoke betta, be cautious. Tank size: 10 gallons +
Fancy Guppies: Need to be kept in groups of three or more. Bright colors and long tail may provoke betta, be very cautious
GloFish: Best kept in schools of 5+. May become nippy, and bright colors may provoke betta. Be cautious. Tank size: 10 to 15 gallons +
Zebra Danios: Best kept in schools of 5+. May become nippy, and fast movements may aggravate betta. Tank size: 10 to 15 gallons +
Glo-Light Tetras: Need schools of 4 or more, 6+ is better. Bright colors may provoke betta, be cautious. Tank size: 10 gallons +
Dwarf Gourami's: Anabantids, bubblenesters, top eaters, colorful. Best placed with female betta's, as the act and look to much like a male betta. Plant tank VERY heavily and have extreme caution. Tank size: 5 gallons+
Small, bright fish may provoke semi aggressive to overly aggressive bettas. Use caution, and watch carefully.
Large, aggressive Fish.