hey if i had a tank i previously use for a geckowould i be able to use it for fish cause i kno icant hold the waer it could leak due to the tank design but is there a way i can make it sustanable to hold water in it?
Take a pic of your tank and show us. Most reptile tanks are compatible with aquatic use. Why do you think it wouldn't hold water? Is the silicone damaged? You can always try it out in your backyard or bathtub ...
Measure the tank and glass thickness also please, some larger reptile tanks do use thinner glass than is required for fish tanks the same size but there is a chart for that.