# Other Aquarium Forums > Freshwater Fauna > Livebearers >  Infected guppy. What to do to prevent neon tetras from "kena-ing"?

## morning breakfast eat

Hi all,

I bought a male guppy 2 days ago, and put it in my tank that has been running for 3+ weeks. The tank already has 6 neon tetras inside which have been healthy and eating very well. I added 3 of them in the first week, and 3 of them in the second week. 

When I looked at my guppy today, I realised he has slight mouth rot. I suspect he also has fin rot since his tail is getting smaller. He also has 2 red spots near his head. I have no idea what to do so I quickly took him out of my tank and put him in a 1 gallon hospital tank.

I have a few questions that I hope brothers in this forum will have answers to..

1) What is wrong with my guppy? I read on some sites that new guppies might be stressed and susceptible to disease. (My tank is 1.5ft and 1/4 planted, i'm not sure about parameters because I don't have test kits =x but then I thought if my tetras are doing well and they're supposed to be more sensitive than guppies, then the more hardy guppy shouldn't have a problem?)

2) What can I do to treat my guppy? Like what should I buy from fish shops? some forums say aquatic salt + yellow powder but I'm not sure 

3) What kind of precautions can I take to ensure that my neon tetras remain healthy? Do I need to do any water change? Do I need to add any medication inside just to make sure they don't get the infection?

Help will be much appreciated!

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