Kuhli loaches swimming all over?

I have a heavily planted 20 gallon tank with guppies, tetras, glass catfish. I also bought 3 kuhli loaches a few days ago. Most of the time they hide under the wood and rocks, but today I did a 50% water change (tank is overstocked). This raised the water temp 3-4 degrees because since it's summer, the tap water comes out hot no matter what. I do float a ziploc bag full of ice in the tank when adding new water to counteract this a bit. Anyway, since the water change, the loaches have been very active, swimming all over the tank. Are they happy because they have new, clean water, or is this a sign of distress because of the change in environment/temp?