Tropical Fish Hobbyist - October 2010

feeding, topping off evaporated water, checking water temperature, checking for dead fish, etc. To make sure you don’t overlook something important, it’s helpful to keep a record of everything you do in relation to the aquariums for about a week. And don’t forget to include in your checklist simple-but-critical steps such as dechlorinating tap water before using it for topoffs.

The
Dreaded Dropsy

I keep killifish and, over the past year or so in several tanks, have lost several prematurely to what I diagnosed as dropsy. Their bellies become swollen, their scales protrude outward, and they swim in an inverted position at about 50 degrees from the bottom. What causes dropsy, how is it cured, and how can it be prevented? I do 30-percent water changes weekly with aged, untreated tap water. My tap water is 7. 6 pH and 100 TDS.

Tony Kline Northumberland, Pennsylvania

First, it’s important to understand that the condition in fish commonly referred to as “dropsy”—swelling of the body, often to the extent that the scales protrude in pinecone-like fashion—is not actually a disease in and of itself. Rather, it’s a symptom of some other underlying disease or environmental problem that damages the internal organs and leads to fluid buildup in the tissues. As you might imagine, there are many potential causes of this symptom, for example kidney or liver disease, internal bacterial infection, viral infection, poor water quality, inappropriate water chemistry, inadequate nutrition, or a combination of factors.

Unfortunately, by the time the symptom of dropsy manifests itself, the odds of curing the affected specimen aren’t especially great even if you are able to identify and remedy the underlying cause. Prevention generally boils down to providing the best possible water conditions for your fish, offering a varied and nutritious diet, quarantining all new specimens, avoiding common pitfalls of overcrowding and overfeeding, and providing species-appropriate water chemistry.

Q
A
Dying
Cardinal
Tetras

Are cardinal tetras more delicate than neon tetras? I have a 29-gallon tank that contains a school of nine neon tetras and an Otocinclus catfish. The neons are doing just fine, but every time I try to add cardinal

Q

tetras to the mix, they die one after another until there are none left. My water parameters are as follows: temperature: 76°F; ammonia: 0; nitrite: 0; nitrate: less than 10 ppm; pH: 7. 2. Can you give me an idea of what I might be doing wrong?