If you can’t make a separate tank for them or remove the fish that try to eat them, all you can do really is add hiding places. Moss and floating plants are great.
Make a 5 gallon tank and breed them in
there alone. Build up the colony and use it as a factory to Zerg rush the main tank. Even if they get eaten there in another 40 days you will have a new army.
Jeffrey561561 
If you can’t make a separate tank for them or remove the fish that try to eat them, all you can do really is add hiding places. Moss and floating plants are great.
Make a 5 gallon tank and breed them in
there alone. Build up the colony and use it as a factory to Zerg rush the main tank. Even if they get eaten there in another 40 days you will have a new army.
What kind of fish do you have?