Guppy Colour Loss/fungus + Sudden Death

[markiey777]

My two female guppy (one of who delivered about 15 babies about 10 days ago) have both developed white areas around their heads and are now losing colour on their flanks. It looks like it could be a fungus but is difficult to tell exactly. The pH (just over 7), nitrite and ammonia (both zero) haven't changed. I put methylene blue in yesterday as advised at the shop and today found the very pretty male guppy dead. I have had the guppies about 3-4 weeks so they have got over moving stress. They have all fed well right from the beginning and the females are behaving normally now.

Some tetra and cory cats in the tank look fine.

Does anyone have any ideas of what the problem is and what I should do.

Thanks

 

[nmonks]

This sounds like slime disease to me. That's a disease where a parasitic infection causes a massive increase in mucous production, which covers the body and hides the colours, making the fish look dull. Eventually, it will kill the fish. The parasite species varies, but aquarists tend to call in "Costia" though that is almost certainly not the correct Latin name for the protozoan involved.

Anyway, you can buy commercial preparations to solve this. However, I've used saltwater dips very effectively. Basically make up seawater (3 grammes of marine mix or cooking-grade uniodinized sea salt to 1 litre of aquarium water). Dip the fish into the seawater for a few minutes at a time. The exact amount of time varies, but with guppies you can probably get away with 5-20 minutes. What you want to do is leave the fish in long enough to allow osmosis to dehydrate the parasites but before permanent harm is done to the guppy. Provided the guppy is swimming or balanced in the net, it's fine; if it starts to roll over, then pull it out at once. You may need to repeat this once or twice more, with a day or two in between dips.

Besides killing the parasite, the saltwater strips off some of the mucous, so your fish will look healthier almost at once.

Saltwater dips can potentially kill a freshwater fish, so perform with caution. If in doubt, do many short-duration dips instead of one or two long-duration ones.

Cheers,

Neale