Cloudy water in pike/ oscar tank

I have an oscar and a pike together both relatively young (oscar ~5in, pike ~6in) in a 20 gallon tank for now. The water recently turned a greenish cloudy color and I did an algae treatment which really didnt help so I did a 80% water change which seemed to help but now a week later its back again . I was wondering if this could be attributed to their waste because they are feed feeders quite often (the pike will down 6 in a matter of seconds) or what. Any ideas would be appreciated, Thanks

 

Green algae can be caused by too much sunlight and also by increased nitrates (caused by overfeeding and excessive fish waste - Oscars in general are known to be messy fish). Keeping the tank out of direct sunlight and doing frequent water changes may help. You should also be looking into getting a larger tank (at least 55 gallons alone for the oscar - 75 would be better considering tank shape versus the natural shape of Oscars), a healthy Oscar should grow at least 1" per month for the first 12 months.

What are you readings for Ammonia, NitrIte and NitrAte?

Also, why are they fed feeder fish quite often? Unless you raise your own feeders pet store feeders are usually not very healthy and a great way to introduce disease into your tank (which is why they should be quarantined in a seperate tank for at least 2-4 weeks). Also feeders don't provide much, if any, nutritional value to your fish consideing that (especially goldfish) are mostly fat, scales and bones. Uneaten feeders will add to your NitrAte count.

 

I would have to agree with Aqueous sounds like too much sunlight and waste. Those fish are very "dirty" fish. the excess waste and feeder fish leftovers are not helping the conditions. They will really need to go into a much bigger tank a small tank cannot support them. Along with freq water changes should help out.

Welcome to the boards...

 

Feeder fish are no problem, though you should try to gutload them with nutritional food, I feed my axolotls feeder fish, i do not quarantine them, but then i trust my source.

The major problem you have, your tank is overcrowded, the fish you have are what i would class as "dirty". You need a larger tank, preferably a 55g as a minimum. Also they require top notch filtration