I have a tropical, freshwater, 40 square metres U-shaped outdoor pond with 0.80 metre depth where I keep my tilapias. Recently, I blocked a section of the pond, making a 6 square metres section for duckweed cultivation, using filters which allow water and very small spawns/fries to pass through. I want to keep the tilapias away so the duckweed can be fully cultivated, so I put 6 bettas (5 females and 1 male) in that section in hopes that they eat any intruding tilapia spawns, but for some reason tilapia spawns still thrive in there (I'm not sure if the bettas actually prey on them or not). What fish would you recommend for me to put in the duckweed section to prey on any intruding tilapia spawns without eating the duckweed?
Note: For the fish you recommend, please write if it also contains some sort of harmful threat(s), ex. if it's poisonous, has sharp/prickly fins, may bite you, ect
Note: For the fish you recommend, please write if it also contains some sort of harmful threat(s), ex. if it's poisonous, has sharp/prickly fins, may bite you, ect
Considering that tilapia can have hundreds of fry per spawn, 6 Bettas would barely make a dent in that population. Even with the Gambusia, you are going to need a number of them ( 50 or more) for any serious population control. If you don't want to do Gambusia, consider using other small to medium sized Cichlids ( Jewels, Acaras, Angelfish, etc) or if you have the space, juvenile Oscars ( Astronotus ocellatus) will eat a lot of fry but as they get larger, will not really eat any fry but will eat them when they turn into a larger meal. None of the fish I mentioned are poisonous or will eat the duckweed.
