Responses
http://www.mangago.zone/read-manga/yami_bl/bt/239155/Vol1_Ch3/2/
It has a fishtank and is about two brothers xD but the ending isn't the same I think
http://www.mangago.zone/read-manga/yami_bl/bt/239155/Vol1_Ch3/1/ ?
It doesn't quite fit your description (only around the edges), but maybe...?
thank you so much but it's not the manga.
Thanks that was it
Looking for a yaoi manga about two brothers. It only had one chapter among a multi-chapter manga. It's confusing and all I remember was that there was a fish tank and one of the brothers died. I think at the end it turned out that the guy didn't have a brother and that he was the one who had died.