Nano Protein skimmer...

[mike31154]

Along with whatever gunk a small skimmer like that will collect, it will also add to the dissolved oxygen levels in your system and that's always a good thing.

[fragbox.ca]

tunze makes a pretty cool little skimmer not sure if it will fit your needs though

[Craigdillman]

On a 5 gallon is a skimmer really worth it considering you can do water changes so easily a 50% wc is like 2 gallons of water and super quick

just my 2 cents

[Craigdillman]

nm someone said this already and beat me to it, guess i should read the whole post lol

[canadianbudz604]

Grab a rio nano skimmer, it takes some time to adjust but actually works on a tank that small. Plus they are like 35$

[Ron99]

I've been using a Hydor Slim Skim on a 22 gallon quarantine tank and it's pretty good. Even the small model might be too much for a 5 gallon though.