Cp 30:7.6 has macche (“the fish”) instead of mañca (“me”). If mañca is accepted, there is no mention of fish in the verse. The original verse may have focused more specifically on the “trove of the crow”, i.e. the deathly drought, from which the waters offer relief.
In Vedic tradition, the waters are invoked to save one from the sin wiped by the crow’s mouth, the kiss of the dread goddess of black death, Nirṛti (Atharva Veda 7.64). The wish to harm the crow is distinctly un-Buddhist and more characteristic of the Atharva. Otherwise, though, the two passages are not similar, except they both end with the same verb.