This study was carried out to assess the fish diseases in different aquaculture farms of north-eastern Bangladesh. Data were collected through questionnaire interview, personal contact and participatory rural appraisals as focus group discussion with different stakeholders. Forty informants from 15 selected aqua farms were interviewed. All interviewees had faced disease problems in their farms. Prevalence of fish diseases varied among districts and farms. Based on the study, total seven diseases were observed in different fish farms. The most prevalent disease in north-eastern Bangladesh was environmental problems (100%) followed by argulosis and dropsy (68%), fin and tail rot (45%), streptococcosis (28%), epizootic ulcerative syndrome (23%) and nutritional diseases (15%). Environmental problems were common in all farms because of high stocking densities, overfeeding, water bodies surrounded with trees and shrubs on the dike and lack of water exchange facility. The highest disease prevalence was found in Sunamganj (32%) followed by Sylhet (24%), Habiganj (23%) and Maulvibazar (21%). The farmers have inadequate knowledge about fish disease. This study also unveiled some fish health management related problems in aquaculture such as lack of assistance from concerned GOs and NGOs officials and poor technical knowledge of private farm owners, lack of technical manpower and lack of suitable therapeutics with proper uses. The information of the study will be helpful for proper management of fish diseases occurred in the north-eastern region of Bangladesh.