Sick Female Guppy

[Mssrod1]

I have a female guppy that does not look well. We bought her in June along with a male. They started reproducing so I moved her and 14 offspring to a 20 gallon tank at the end of September. Recently I noticed she was either staying at top or bottom of tank and not as active with tail bent down. At the time, she looked like she was ready to hatch so I thought it was just from late term pregnancy. I have not seen any new fry but I also no longer see eggs. She is still lethargic and I noticed a white cobwebby string off of one fin (pic attached) have not seen her scratching on decor or gravel. I did add a tank divider 2 weeks ago to try to separate male from female guppies. All other tank mates look healthy. I would appreciate any help in finding appropriate treatment.

20 gallon tank with Top fin silenstream filter, PH 7 Temp 80-82, nitrites 0, nitrates 40, feed tropical fish flakes. 15 guppies and 2 otocinclus catfish. Water changes last week.

 

[Aiken Drum]

Do you know if you have ammonia present in your water test?

 

[Mssrod1]

No - test strip did not include ammonia. None of the other tank mates are exhibiting any problems.

 

[Mssrod1]

I bought an ammonia kit and it tested at 0.25 ppm. Yesterday I thought I saw a change to mouth area such as very small cottony growths, so I started erythromycin treatment.

 

[Aiken Drum]

Are you quarantining the fish or treating the whole tank?

 

[Mssrod1]

I am treating tank. She is my oldest fish and so all fish in tank have been exposed to her. Working on setting up a quarantine tank for future use (smaller tank I have is currently occupied).

 

[Mssrod1]

Guppy is more active today after adding erythromycin last night. She is also looking for food today. She has not been eating for several days and lethargic, so I think the erythromycin maybe helping.

 

[Aiken Drum]

I am treating tank. She is my oldest fish and so all fish in tank have been exposed to her. Working on setting up a quarantine tank for future use (smaller tank I have is currently occupied).

Just be aware that erythromycin is antibiotic and can also kill off the beneficial bacteria responsible for your cycle. Keep an eye on your water parameters.