Zebra Danio

[tdiii]

I have a 29 gallon tank that is 7 weeks old. I used a buddy's filter media to help jump start the cycle. Currently I have 3 danio (I had one die last night) and two dwarf gouromis. I tried adding a otocinclus two days ago and it died during the night. Today I noticed a weird growth on my danios underbelly behind the pectoral fin. It's a uniform bump the same width as his body. This danio is still 'under warranty'. Should I exchange him? Is this a disease that I need to worry about my other fish catching?

I just tested my water and ammonia was 0.25 ppm (which is the first time I've had detectable ammonia) nitrite is 0 nitrate is 20. Ph is 8.0. I just don't want anymore fish to die so help would be appreciated.

 

[tdiii]

BTW, I am running an AC 300, I do weekly 5 gallon water changes, and I'm experiancinga a bloom of brown spot algea (diatom?). I have a few live plants (anacharis, java fern and a red lily) and feed a diet of omega flake food and frozen bloodworms.

 

[GSD]

it sounds like the tank isnt fully cycled.Is the temp etc ok aswell?It could be a parasite

 

[WILDER]

Need to no water stats in ammonia,nirite,nitrae,and ph, the growth is it filled with liquid or hard, what colour is it.

 

[tdiii]

My water stats are in the first post. They have been really steady the entire time I've had this aquarium. However, I retested the Ammonia today and it is 0.25 ppm. Why am I having a little ammonia spike even though I haven't had detectable ammonia before?

The water temperature is 77 degrees F. The growth looks hard and is the same color as the underside of the danio's belly.