My favorite freshwater fish is the German blue ram (Mikrogeophagus ramirezi). However, every time I try keeping these beautiful fish they die. I have checked my water parameters and it seems all right: (pH: 7.2, nitrate: 35 ppm, nitrite: 0 ppm, ammonia: 0 ppm). None of the other tropical fish in the aquarium show any signs of harassing the rams. freshwater angelfish, tetras, and other soft water fish all thrive in my aquarium. Why won’t the blue rams?
I have had success with many tough-to-keep tropical fish on both the saltwater and freshwater sides of the hobby. But German blue rams where one species I could never get to thrive or even survive for very long. I tried numerous tactics (keeping them in pairs in smaller aquariums, keeping them in large aquariums, keeping them with thriving, tough to keep fish, etc.) though none proved successful. On a strange and aggravating flipside I know some people who keep German blue rams and do nothing special to keep them alive. I even know of cases where rams kept in ordinary community aquariums have bred and produced viable spawn. Each time I tried keeping rams (even in a discus fish aquarium that received daily 100 percent water changes) they perished for no apparent reason. So the short answer to your question is that I have no idea why you are struggling trying to keep German blue rams, though let’s look at some possible problems.
Rams, like discus fish, require very pristine, soft water. I saw that you noted a nitrate reading of 35 ppm. While this would be acceptable for many freshwater species I think German blue rams may not tolerate that nitrate level. The best way to lower nitrate levels in the freshwater aquarium is through frequent partial water changes. When keeping tropical fish like rams and discus fish I often recommend bi-daily 25 percent water changes to keep nutrients in check. This may seem like a hefty load but a good water change schedule is an overall aquarium problem preventative. Rams are shy tropical fish that often struggle to eat in crowded community settings. Also, a pH rating of 7.2 is a little steep for the South American rams. I would strive for a pH level of 6.8 and see if your success rate increases.
Like I stated before I have seen rams thrive in community aquariums but I don’t recommend it. Smaller (20- to 30-gallon) aquariums make good quarters for German blue rams when kept in pairs and also give aquarists an edge on water maintenance because a 25 percent water change isn’t that large in a 20-gallon aquarium.
You don’t mention your fish showing any signs of illness before dying so it’s unlikely that they were affected by a parasite. However implementing a UV Sterilizer on the ram’s aquarium may help control some previously overlooked bacteria or parasite problem.
The solution that worked for me was giving up the idea of keeping German blue rams altogether. I started keeping the Bolivian rams (Mikrogeophagus altispinosus) and found them to be far hardier. Why some people keep rams with relative ease and others struggle I don’t know, though it is certain that these little South American fish pack a punch in the looks department. You may also find that other dwarf cichlids like the Apistogramma species or others work better in your aquarium.