Our fish tank was having an ammonia spike around 0.5 ppm and we Googled how we can lower it. People on forums were talking about Seachem Prime and we’ve read positive reviews about it.
We went to PetSmart and bought one. We read the instruction and used 1 capful. The fish looked fine the first few minutes and we thought it won’t harm them. We had lunch and when we came back, almost all of our fish are dead. It was really shocking to see how fast it happened. Probably less than 30 minutes.
Some fish that were still alive started to jump out of the fish tank. According to Seachem Prime instruction, it is safe to use even 5x the amount. 1 capful was for 50gal and we have 35gal, so even if it’s only a little but more, it should be fine.
But it seems like it was dangerously high and it instantly depleted all the oxygen in the water, suffocating all the fish. The product should at least have a warning about this.
We were trying to save our fish and we ended up killing almost 80% of them. Really tragic and sad day.
Instead of saving them, we ended up burring them in our backyard. RIP fishes.
To be honest, I don’t think it was the prime that killed your fish. I think you didn’t use enough prime. You essentially used a dose for new water, as if you were neutralizing tap water to top up your tank. Double dose is for tap water with higher than usual chloramines. 5x is for emergencies such as what you were experiencing. So the fish likely died from ammonia and nitrite poisoning. I have used prime to save fish a few times. I used the 5x dosage though.
This has happened twice with us. First time when i setup a smaller tank for a silver dollar that we wanted to isolate. Used Prime as per reccommended dosage. Fish started going side ways, could not hold itself steady. It died in about a few hours. There was some unusual slime from the mouth. We kinda stopped using Prime after that.
Second occassion when the wify accidently added Prime when doing a water change. Again recommended dosage. Luckiy as soon as i found out, checked the fish. Same symptoms.not holding steady. Quickly changed the water twice to get it out of the filters, added some water from another tank. And the fish survived with one tetra as a casualty.
Am thinking Prime promotes fish to produce protective slime. Maybe it does that too much. Or it maybe the supposed short term oxygen depletion.
Well whichever the reason never using Prime again.
I just had this exact same experience. I have never used prime until the last week. I dosed prime in accordance with the directions in my 125. 3 days ago I woke up to find a dead rainbow shark that has been in the tank about a month. The next morning all the fish in the tank were in various stages of dying. Today I set up a quarantine to make sure my beloved panda cory’s made it. Dosed my perfectly cycled tank water with a cycled sponge filter with a 2x dose of prime. Within 30 seconds the cory’s stopped moving completely. Quickly moved them back to the main tank while keeping them in the tank. After forcing water through their gills for probably 5 minutes they both came back to life but were and still are breathing heavy. Threw out the prime tonight. It’s literally the only variable changed.