[Lupin]

Hi and welcome aboard.:wave:

I wouldn't keep more than 1 flying fox. Nor would I do with SAEs. They are quite aggressive among themselves and a large tank with lots of hiding places will require you if you want to keep more than 1.

All tetras may have a chance to spawn but survival rate of eggs is extremely slim. Tetra eggs are known to be sensitive to light. Not to mention some bottom dwellers sifting the subtrate and other decors until they can eat all the eggs.:wink2:

Dwarf gouramis will need to be isolated when they spawn if you want the fry to survive. A lot of fry will never survive in a community. I would let nature take its course unless you are really serious in breeding specific kinds of fish. Unless you do, you'll need several tanks for rearing and breeding purposes.

As for labeos(sharks), I am opposed to keeping them in a 30 gallons tank. They are very aggressive and some can reach 5 inches and will eventually harass your fish. Bala sharks are not an option either. You'll need to keep them in shoals as they are very skittish thus prone to accidents or injuries. A shoal alone will require you a 150 gallons tank as they can reach 12 inches in time.

In a 30 gallons tank, you are not expected to keep fish that grow quite large other than fish that grow to 4 inches max.
I would recommend apistogrammas as your best choice of cichlids. Do more research on them. Some are quite delicate and will require 6 months tank maturation. Bolivian rams would be a good option. If you want blue rams(Microgeophagus ramirezi), consider tank maturation by about 6 months. They are quite sensitive to nitrites.
I wouldn't go for kribensis(Pelvicachromis pulcher). They get extremely aggressive during spawning time and will eventually attack your other fish in the attempts to save their fry.

As for bettas, I'd keep the male betta alone in a 5 gallons tank. 10 gallons would be even better for more space. I wouldn't, however, keep a female together with a male in one tank. Males are known to harass even the females and you don't want to see him harassing his mate to death.

If you want shoaling fish, I'd recommend you to start with robust and peaceful species. You can go over harlequin rasboras, diamond tetras, lemon tetras and beacon tetras.

For more bottom dwellers, you can't go wrong keeping kuhli loaches or corydoras.

Good luck.

 

[Lupin]

I would only assume your flying fox are maybe young. Young ones don't tend to fight but as they grow older, they tend to become aggressive against each other.

Livebearers will often breed a lot but you will need tetras to eliminate all the fry as livebearers tend to produce a lot that overcrowded conditions becomes an issue.

Danios and cherry barbs are one of the easiest cyprinids to breed. They are egg layers and only a few eggs mya survivie provided you have thickets of plants. Cabombas are often used by cherry barbs to deposit their eggs. Danios are egg scatterers and will spread the eggs all over the place hence the word "scatterer".:wink2:

I'd forget getting any of the anabantids(dwarf gourami and bettas). Either of them is a recipe for disasters. Male dwarf gouramis IME tend to become aggressive once they establish territories on the surface level. Even without the females, both species get aggressive. Believe me, there are times you may get a docile male but you will be unlucky if the fish you got is very aggressive. I'd avoid both species unless you have other tanks for them.