Fungus on Peppermint Bristlenose

Question
Hi Jaymie,
We have have recently started to own Peppermint Bristlenose. We have set up a 4ft tank, 200ltrs, specifically for them. We have about 15mm of gravel on the bottom, numerous pieces of driftwood, on with a live plant growing on it and several bristlenose caves. We have a 4ft air curtain, and Eheim 2217 canister filter and a 1800lt/hr internal power head, 300 watt heater. Temp is 25 degrees celcius, ph is about 7.2. No ammonia or nitrite. We let the tank cycle for two weeks before introducing fish.

Fish: Two adult males, two adult females, two juveniles approx 1.5cm and approx 50 common bristlenose fry in a net frysaver.

Problem :Yesterday we noticed one of the females dead. We did our regular gravel vac and water change 40%
Today one of the males is dead. We have also noticed that the remaining fish (all but one of the juvenile peppermints) are covered head to toe in green mould or fungus and also have fin damage. We have treated today with an organic treatment Primafix, main ingredient pimenta race mosa (bay oil). Will this be enough. The other female looks like she may not make it but is hanging in there. I have been all over the internet and cannot find information on anything that will safely treat the Peppermints.

Can you help?

Thanks so much. :)
Kind Regards,
Wendy and Gavin

Answer
Wendy,
Sorry to hear you are having problems. There are a couple of things. Firstly, a tank needs at least 6 weeks to cycle. Make sure you are testing the water with a liquid testing kit, not the strips. Since you only started the cycle process, the ammonia and nitrites should be very high. In the first week of a cycle, not much happens in the tank. During the end of the second week or beginning of the third week, the first of 2 bacteria blooms sets in. This is the bacteria that can and often does, kill any fish in the tank. That bacteria sits in the water for about 1 to 2 weeks. When that bacteria is taken care of by the filter the second bacteria bloom sets in. This is the good stuff that the filter, gravel and fish need to stay healthy. I believe the main problem you are having is not fully cycling the tank. Another problem is the tank is grossly over stalked. Even though you have fry, you had approx 56 fish in the tank. The fry cannot survive in the net frysaver. They should be in their own tank. The other problems are because of bad water quality due to not cycling and being over crowded. As to getting the algae off the fish, that I do not know. I have never come across that problem. You might try another expert on the website. Algae grows in a tank that is either not cleaned properly, the tank light is the wrong kind, or it is left on too long. I have never used any product to aid in the removal of algae. I am hoping that maybe if you try another expert they will be able to help you with that problem.