Well from my experience male bettas are really pretty gentle fish. ( they are only mean towards other bettas,gouramis,cichlids, well really just plain territorial non-communal fish.) When i placed roger in my 17 gallon community tank he did just fine with my platys, (dwarf and normal sized)guppies, (male and female) rainbow tetra, ( i wouldn't recomend him though he is an old fella about 2-3 years old so he is gentle now but he wasn't always this friendly) and my harlequin rasbora tetras. Male bettas can also be housed with corydoras catfish, ottos, white cloud mountain minnows,and mollies. By the way, tetras have been accused fin nippers so i would take caution in adding them though i have had no trouble with them at all and some male bettas confuse male guppies for other males because of the trailing fins and bright colors but again i have had no trouble with them. one tankmate i want to warn you about are tiger barbs. ( the little buggers killed nearly my whole commmunity a while back and i had to beg my grandpa to let me return them) don't buy them unless you are willing to start a tank with ONLY tiger barbs. Anyway, hope this helped!
Cherry and Ghost Shrimp: These small, scavenging invertebrates are good tank mates for bettas in that they produce minimal waste, do not mind stagnant water, and can be kept in the same temperature range of bettas (though it will mean faster development and thus a shorter lifespan). Unfortunately, some bettas think ghost shrimp are a large, overpriced snack; if you see your betta harassing a shrimp, remove it promptly. You must also never use additives or medications containing copper to a betta tank containing shrimp, as it is highly toxic to these animals - as well as all other aquatic invertebrates.
Apple Snails: These colorful snails are an active, attractive addition to a betta tank. They are capable of surviving in lower oxygen environments, and tolerate tropical temperatures - with some reduction in overall lifespan due to the increased speed of development. They also adapt quickly to nipping and are generally too large for most bettas to kill or consume. However, the ideal conditions of both species is compromised to keep both in the same tank; apple snails do prefer oxygenated, filtered water and slightly lower temperatures. What's more, they demand for survival hard, slightly base water - the opposite of the betta's soft, acidic preferences.
African Dwarf Frogs: These tiny aquatic frogs are considered one of the best candidates for a betta's tank mate. The share the same preference for stagnant, warm, soft water, and are not as likely as other fish to attract a betta's aggression. However, it is essential to keep water conditions pristine, as they are very prone to bacterial infections with even moderate declines in water quality. What's more, as with invertebrates, African Dwarf Frogs have no tolerance for copper. Finally, be sure your ADF is getting sufficient nutrition; because both bettas and ADFs are carnivores, they will be at odds with each other for food competition. It may be wise to feed the betta or frog in another container, as food competition can illicit aggressive behavior.
Otoclinus Catfish: Many betta keepers house otoclinus catfish with their bettas. These small, low-waste fish are fantastic additions to planted tanks and greatly reduce algae. They are fast without being distracting, dully colored, and do not share the same water space as bettas - thus, they seldom encourage aggressive responses from bettas. However, they require an extremely stable environment, and thus require a matured, cycled tank - preferably planted. When stressed by fluctuations in water temperature and parameters, their digestive systems may shut down. It is also important that harassment from the betta be monitored, as this form of stress can be equally serious. Finally, remember that otos are a social species that prefer living in larger groups.
White Cloud Mountain Minnows For a tank mate more dynamic than bottom feeders, the white cloud mountain minnow is often an acceptable choice. This small, peaceful fish does not tend to nip fins, and can usually escape a betta's aggression with ease. They are very hardy, and inexpensive to purchase. However, they also prefer cooler water, so your betta's tank will need to be kept at the lower end of the preferred range. Also, a tank of at least 10g is preferred to 5g in this instance, as WCMMs are very active; your betta will need plenty of hides and plants to avoid feeling stressed.
Neon Tetras: In many ways compatible with bettas, neon tetras share a similar preference for pH, temperature, planting and light conditions. However, they may nip fins, and a minimum of six fish is essential - meaning no tanks under 10g
But i suggest that if you do decide to add any that you moniter very carefuly for the first couple of days to weeks.
yes, it depends on the personality of your betta. my first betta's tankmates were mollies. they did well together. however, my 2nd betta always flares when he sees my mollies swimming near the divider so i don't dare mix them up.
Astro, I got attacked for suggesting WCMM with a Betta in a large tank. I'm glad someone else thinks they can cohabitate well, especially if you've witnessed it over a long period of time, which I have. Granted I have a female betta, which aren't typically as aggressive as males, but then again it depends on the fish. I would highly suggest WCMM together with a betta. Incredibly hardy and curious fish. I love them with my girl and they hardly pay each other any attention. Sometimes the betta trails behind one for fun I suppose. Watching him and seeing what it's doing.
The reason people criticised you was because you were keeping the tank between 68 and 72, which is too cold for bettas. They are tropical and should be in temperatures 10 degrees higher than that. You are also not keeping them in a proper school, which will stress them, and in a 3.5 gallon tank, so you are very overstocked.
I don't see that as the case. The tank is heavily planted, constantly reads out at 0.0ppm in ammonia levels everdyday, and I do 50% water changes every other day. My girl eats and flares and swims around doing her thing
Even if you are doing that much to cope with the bioload, it isn't fair to keep a fish as active as a minnow in a tank that small, and it isn't fair to keep schooling fish without a school. This will stress them out, and stressed fish are more susceptible to sickness.
Furthermore, even though your betta is currently healthy, keeping her at a lower temperature is depressing her immune system. It creates a higher risk of her getting ill and will make it harder for her to recover if she does.
Whilst it may be working at the moment, there is still no reason to risk a fish's health by keeping it in conditions so far from the optimum.