I'd use a heater in your feeder tank - even though goldfish (assuming those are the ones you are planning to use) are coldwater fish, they'll do fine in warmer water.
The more equal the water temperature in both tanks is, the less the temperature shock will be - temperature shock is one of the most common triggers for ick, and ick is present (in a dormant state) in every fish tank.
Other than that, I'd keep the feeders quarantained for at least 2 weeks, as said in a tank with a medium dosage of salt (1 tablespoon per 10 gallons): during this period, gutload them (ie. stuff them with high quality foods), so your piranha's will get an extra nutritional bonus
![]()
btw: if possible, I'd get other fish than goldfish - they, just like all other cyprinid fish (barbs, danio's, carps, koi, goldfish) contain growth-inhibiting hormones that may pose a health hazard to your piranha's - it's a long-term process, so you will only notice it when the damage is already done.
Instead of cyprinids, go with tetra's, lifebearers or cichlids (you could even try to breed them, to save some cash...)
The more equal the water temperature in both tanks is, the less the temperature shock will be - temperature shock is one of the most common triggers for ick, and ick is present (in a dormant state) in every fish tank.
Other than that, I'd keep the feeders quarantained for at least 2 weeks, as said in a tank with a medium dosage of salt (1 tablespoon per 10 gallons): during this period, gutload them (ie. stuff them with high quality foods), so your piranha's will get an extra nutritional bonus
btw: if possible, I'd get other fish than goldfish - they, just like all other cyprinid fish (barbs, danio's, carps, koi, goldfish) contain growth-inhibiting hormones that may pose a health hazard to your piranha's - it's a long-term process, so you will only notice it when the damage is already done.
Instead of cyprinids, go with tetra's, lifebearers or cichlids (you could even try to breed them, to save some cash...)
