u/Sudden-Papaya-5880

My 20 gallon is finally perfect I do have a mix of live and some fake plants but I was very careful in choosing as it can snag fins - I have cherry my veil tail betta, my mystery snails blue cheese, toast,and champagne. My chopstick snail peppercorn and a little bladder snail named crumb. My amano shrimp oatmeal and then 9 rasboras I just refer to as the girls. I’m a new fish keeper and it is so fun to care for them 🐟🌱

Hi I got Marcel 2 weeks ago and now I notice this around his eye and head what could it be