They need temps in the range of 72 to 75 with the lower end of the range being better.
I would not rely on floating ice other than in an emergency. Hmmmm pretty cool in NY in the summer….. I grew up in NY and have memories of miserably hot summers. Where do you live in NY? You need a reliable way of keeping the temp down and stable all year round.
In a smaller tank a couple of small plastic 6 to 8" clip on fans blowing across the water surface could work. This might not be sufficient, without an air conditioner during a heat wave like we experienced across the country this summer.