Consult about cold water fish culture

I want to use mountain spring water to raise cold water fish (such as rainbow trout). The area is about 4-5 mu. There is plenty of water. It is about 15 ℃ all the year round. What aspects should I pay attention to? Where can I buy seeds? Do you know anything? Please give me some advice. -- paying attention to. -- suggest the landlord to observe whether the water source is stable? Has the environment been polluted? If the external environment ok, it will be fine-- such a good resource is very rare, have you examined the market? Seedlings are easy-ding support! -- it seems that there are not many people in aquatic products, and the water source is stable and the water quality has not been measured. 4-5 mu of paddy fields have been replaced from less than 100 of the effluent, and now they have been dug into ponds more than 2m deep, and the four sides have been completed, but there are no blocks in the middle, because there is no technology and no specialized farming. Let's do it the old way. The traffic is quite convenient, 40 minutes to the county seat; 2 hours' drive in the city, the specific market is not clear