Hello i got a redtail about a month ago he is about 18 inchs long and very healthy. the problem is his gills are curled up towards his head what causes this and is it a health problem. if it is can i fix it. he was in a 55 gallon tank when i bought him and now he is in my 150 gallon tank with my 18 inch oscar and breeding pair of chocolate cichlids. Please help
to MFK
...18 inches---15 max...