Let's keep our eyes on the ...

Let's keep our eyes on the ball.   Is this a commercial fish production operations?  If it is, then they want a lot of fish in a small area  this changes everything.  It is different from a small pond in a farmer's field.  If this  is a commercial production we are not talking about the aquatic cycle that we studied in college.  The operation would want to raise a lot of fish as fast as possible to make some money!  

Because there are the possibility of several different problems,  everyone can be correct in their thinking about the problem.

 The question to answer is define the problem in specific terms including such as: commercial operation, pounds of fish havested, how often is it harvested, how much feed is used, how often are the fish fed, what are the chemical tests or are they even testing, what are the bacteria tests - if tested, what type of fish are being raised:e.g. tilapia, shrimp or catfish?

Is this an aquaculture operation that needs some quality control and proper production methods, or just a pond in a farmers, backyard?

Aquaculture can be a big operation, or a small one.