Another thread, another problem.

Noticed a few days back that the albino shark (Epalzeorhynchos munense) is, simply put, poohing white...

Wasn't sure if this was normal or not so checked online and was kind of disturbed to find out that this was either constipation or possible parasites.

Problem I've got is he's showing symptons of both, but not all. I don't want to treat the tank for parasites if there aren't any, specially with medication seemingly like gold dust in the UK...

There's little dividers in the faeces, like little air bubbles. Aside from that and the colour - it's all looking fine. No "long thread like" items in it or hanging from his behind. Anus isn't swollen or red as far as I can tell. He's eating well (a little too well) and is just as active as he's always been

I'm currently starving him for a couple days and then will give him some peas. If it's constipation that should help.

Tank is currently cycling due to a balls up with the couple I bought the tank off (media got thrown away).

Ammonia is below 0.25, nitrite is 0, nitrate is 20~40 ppm due to dodgy tap water and pH is around 8. Temperature is 25~26.

64l aquarium, filtered with an interpet PF2 that will be replaced in the next few days with an AC 50.

Just as a side question, how much should I clean the filter sponge media? I know it's best to leave it alone during cycling but the filter was on its way to being clogged up with grime. The sponges aren't doing the best job of catching muck, some of it gets trapped and clogs the sponge up quick or it just lets it through completely due to being so porous...

Thanks in advance as always!