Identification uncertainty and an inappropriate transfer

An angler catches an unfamiliar fish and notices barbels but has not compared their number, position or the other body features. A companion assumes that any fish with barbels must be a common carp. Another fish has a scientific tag and is below an explicitly applicable minimum length. The angler proposes keeping it because the tag appears valuable. At the end of the visit, live baitfish remain in a container and someone suggests releasing them in a different pond on the way home. No stocking authority or relevant exception is supplied. The decisions require actual identification, protection, traceable information and biosecurity rather than a convenient generalization from one body part.