Fish Loss

[slowal]

Hi my name is Alan and I am new to this forum. I have an issue with immature Guppies dying at around 3 months old. They tend to spend all their time on the bottom of the tank and look rather lean. Other Guppies born at the same time do swim around freely and would appear to be ok.

 

[fluttermoth]

Welcome to the forum, Alan.
 
What size is your tank? Is your water hard or soft? Is the tank filtered? What temperature is it kept at? How large and how frequent are your water changes? What are you feeding the fish? Do the fish show any other symptoms; white, stringy poops, perhaps, or discolouration?
 
Sorry for all the questions, but the more information we have, the better we can help you work out what the problem is

 

[slowal]

Hi,
 
Thank you for your reply, the tank is 65ltr. with hard water which has filter on 24/7. The temp is 25 degrees and I do a 20% water change every 2 weeks.
Fish show no sign of disease, but do look rather thin compared to the usual Guppy female shape.
 
Currently feed them King British tropical fish flake. This is a community tank with Neon Tetras, Harlequins, Molly's and Sword-tails all of which are healthy fish

 

[fluttermoth]

I suspect your problem is going to be very high nitrate levels.
 
I hope I don't sound too harsh, but that's a lot of fish in a small tank, and your water changes are too small and too infrequent.
 
You need to get your water tested as I think the nitrate has probably built up over time; your older fish are acclimatised to it now, but the growing fry will be less tolerant.
 
You'll need to up your water change regimen, but you'll need to do it gradually so as not to shock the fish, so get it tested first. If you have a shop do the tests for you, get them to write down the actual numbers. Don't let them just say, "it's fine" or, "a bit high"