English Translation
This morning, I went to a fish selling counter and the flying fish was very fresh and also on sale.
FYI: the Japanese author posted many unnatural sentences on Tatoeba. I guess he is not a native speaker.
ピチピチ or ぴちぴち itself is a natural collocation for fish, but I find the overall word order is a bit unnatural and very wordy. My alternative sentence is:
今朝魚屋に行ったら、ピチピチの飛び魚が特売になってました。
お魚屋さん is also okay. But we don’t say 対面販売のお魚屋さん. 魚屋 is supposed to be a counter selling. So, drop 対面販売.
ぴちぴち itself means “fresh and lively”. So, you don’t need 新鮮 along with ピチピチ.