Thanks for the detailed reply. I have 1.5 gallon one [ https://www.amazon.com/Tetra-LED-Aquarium-Gallon-Cube/dp/B00CJJHGZC/ref=sr_1_4?ie=UTF8&qid=1547600005&sr=8-4&keywords=tetra+1.5+gallon+aquarium ]. I have quick start to the water. It does not looks like breathing heavy or struggling to stay up. Also I will get the water checked soon.