Salim bin Abi al-Ja'd (may Allah have mercy on him) says: We had a neighbour who was a fishmonger (sammak); he owed a man 50 dirhams, and he kept giving him fish as gifts. He came to Ibn Abbas (may Allah be pleased with them both) and asked him, and Ibn Abbas (may Allah be pleased with them both) said: Count against it what he gave you as gifts.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10931