Does he look sick at all? Any signs of early hole in the head? Any stringy white poop or mucous? Flicking against the floor or objects?
Still eating and pooping well?
Is your tank overly hot or low in oxygen with little surface agitation? That can make fish lethargic.
Once a week is good for water changes, although it depends how bad your water is. Best to get it tested first.
Remember that water changes aren't just to get out Nitrates, they are to replenish the good stuff in the water that the tank consumes. Through osmosis; fish, bacteria and plants use the kh, minerals and trace elements in the water, and we have to put them back in with a water change. If you have no Nitrates, you still need to change the water, and once a week is what's recommended.
I've literally had red devils since I was a little girl, they are very hardy fish, they aren't overly sensitive to pH, gh and bad water in my experience, but you don't know what he was raised in. When I was little my dad dumped freezing cold hose water in with our old gal, which is absolutely full of Nitrates and stuff in our area, 40-50ppm, pH of almost 9, gh of over 25!! Lol. Poor old gal. She was always fine. Cold, but fine! You'd be amazed how hardy a devil can be. Try not to worry too much if your water isn't perfect for him. Most cichlids are adaptable within reason.
I have the api freshwater kit. I don't know if it's the best, but it works well for me. I also recommend getting the api kh (pH buffering) gh (water hardness) and phosphate (algae) test eventually, then you have a full kit and you can problem solve any issues more effectively, and it makes people's lives easier on here if you can list it for them! It also helps to keep track of changes yourself. I keep mine recorded on a chart, plus I have a seneye, but I am rather ocd about my water quality because I have some irreplaceably rare and pricey fish.
LOL
kewpiefishypewpie
'lazy gills'. Love it!
