Jeremy helps one of our readers with setting up the filtration for their fish-only saltwater aquarium
Are fish-only marine tanks still set up these days, or are most people now just going down the reef tank route? I'd like to keep a pufferfish or a trigger as a character fish and wondered about the best way to do this when it comes to filtration.
Am I better off with a large external power filter for a fish-only tank? Do I need a protein skimmer? The tank I have available is 180x60x60cm (6x2x2’).
PAUL HEPWORTH
Related article: Marine fish with character.
Jeremy's Advice on Marine Filtration
Fish-only marine tanks are definitely still ‘a thing’. So many desirable saltwater fish species simply aren’t reef-safe. These include puffers, triggers, lionfish, large wrasses, large angelfish, and butterflyfish.
Nitrate is the enemy of fish-only tanks containing bigger fish. The large quantities of rich foods, like cockles, mussels, prawns, and lancefish, create huge amounts of nitrogenous waste. Your biological filtration converts this waste eventually into nitrate.
Two large canister filters will deal with the ammonia and nitrite, although nitrate will build up rapidly. Ideally, you want to include marine safe nitrate removal resins alongside your other filter media to reduce this. I’d also add a protein skimmer, which can help to remove some of the waste before it’s converted into nitrate reducing the pressure on your filter.
Photo by Neil Hepworth
The best option, however, would be a sump-based system with a roller mat filter (pictured below) to automatically catch and remove solid waste. Follow this up with a large protein skimmer, followed by lots of marine-safe ceramic media, carbon, and phosphate remover. Products like Red Sea’s NoPox can also be added to systems running protein skimmers and will help lower nitrate levels by encouraging additional forms of bacteria.
Related article: What can I stock with a trigger and puffer?