I have an 18" sanitwongsei in a very small indoor pond (300 gallon). When I moved him from his previous tank (100gallon) he did not eat for 3 months. People have mentioned that these fish will do that and that no worries-they will eventually eat. Maybe it is because they are a migratory species-when they are moved it messes with their head perhaps? Mine was about 9" a year ago and is now heading to 18-20" real fast. I expect him to do the same thing when I move him into his next tank (1000 gallon+). They definitely need alot of swimming room-We call ours Pacer since that is what he does all day