I just added a new swordtail to my tank a few days ago. I also have 3 brilliant rasboras and a cory catfish. It's 10 gallon tank. The swordtail is pulling long strings of poop. I've been feeding them flakes and the other fish are fine, but maybe the swordtail has different dietary needs? I fed him some peas and he was fine for a little bit, but when I went back to flakes, he went back to super-long poop. Should I swap out the flakes for something else or do the pea thing routinely or is there something I'm missing?