Letargic Fantail

[Dahlia_Cherry]

I was wondering weather lethargy could possibly be a sign that my Fantail "Lucinda" is starting to age? She seems to spend most of her time sleeping under the filter... I've read about ammonia levels being a contributing factor to, but don't think thats the case because my other fantail "Marv" is fighting fit same as always. He just occasionally snuggles up behind Lucinda for a nap.

Thanks in advance,
Dahlia.

[wombat1100]

The first step in any tank problem is to check the water quality, have you checked the parameters of your tank? if you have can you please post them here for more advice.