hello everyone, I am new to all of this Betta keeping stuff so please no judgement. I recently purchased a 16L tank for my Betta. I have also put in three neon tetras, a brittlenose catfish and a medium mystery snail. In the first two days the snail has died and one of the neons had died as well. I was expecting some deaths seeing as I had not waited a week for the bacteria to grow. I suspect the tetra and snail died due to either that or they didn't like the temperature of the water or other abiotic factors. The only problem is that my Betta has been furiously chasing the other two tetras around the tank for a few days. I'm worried as I know that he can easily kill them. He has no problem with the catfish. I thought he may have been unhappy or sick or hungry, but upon further inspection found a massive bubble nest which either meant he's ready to mate or he's happy with his environment. I would like for these fish to live in harmony but I don't want any to die from constantly swimming away from the Betta in fear. I have seen the solutions like add in more plants and decorations, which would be a good idea but the plants I have now the tetras don't use, they just swim in the open. Somebody please help as I'm worried about these tetras and do not think they will last much longer.