Help! 2 of my 4 guppies have white stringy poop. They have good appetite and only one is slightly lethargic but always has been since he tends to be picked on. I recently introduced them to a new tank with 5 neon tetras and two ottos. The guppies seem to be the only 2 with issues. I’m not sure if it’s stress or could be a parasite. I did recently add two new plants. Help what is this and how do I fix it? The cucumber is for constipation in case it’s that.