Hey, I have had a 20 gallon high planted aquarium for more than a month now. I do not have test kits but I have luckily gone through my fish cycle with my fish in (fishes were an impulse buy, seller said its perfectly fine). I know the cycle is complete because I had gravel from a cycled tank, and most importantly the fish look healthy and the plants are growing fresh leaves. I do small water changes after every 2 days, and an occasional big one. This and having a lot of plants has helped me a lot with balancing the tank without a test kit. I have slightly cleaned my filter sponge(in tank water ofc) once because it was clogging and overfilling the sump. My filter is an on-the-top filter with a rainpipe that rains water over a sponge and biomedia. I used to have 6 black skirt tetras at first. Then I added 4 sakura cherry shrimp and 3(mff) fancy guppies after a week or so. 4 days went by in harmony, then I woke up one morning to find that my black skirts have eaten the entire tail fin on one of my guppy females. I immediately returned the tetra school and my tank has had 2 guppies ever since. But after this happened, My shrimp who used to hide under my driftwood now swim and graze around the tank freely and the guppies had taken over the entire tank. 4 days later, my guppy gave birth to 10 babies, out of which i took 4 out in a fishbowl with some hornwort and an airstone. I did 50% waterchanges in that daily, all 4 are still healthy. However, 4 fry were left in the tank that found a hiding spot between the plants I managed to uproot while fishing out the fry. I let the plant lump be. Now the fry are big enough to be in a net mesh, so all 8(?) of them are in it within the tank. I added the floating plants to the mesh box and placed it above an airstone. Now the problem is: My horrifying experience with black skirt tetras has me worried about any new tankmates. I enjoy my tank as is, but I really want a community tank. I have a few options to follow now: 1. Buy 10 Rummynose Tetras, 2. Buy 10 Glowlight Tetras, 3. 10 neon tetras, 3. No more fish. Please tell me how to go on from here. Any suggestions, improvements are welcome. I could sell off my guppy fry in 2 months, and hence delay purchasing more tetras till then. Anyone here that has kept glowlight tetras with guppy? do they fin nip? are they aggressive?