Last night I noticed a weird transparent growth on the side of one neon tetra just above and behind her pectoral fin. It's like a transparent 'bubble' about the same diameter of her eye and protruding about 1/16". She's also pretty fat, quite a bit chunkier than everybody else, and is gasping a little. Oh and it turns out that unfortunately our nitrite level is 1.6 ppm (girlfriend did wrong test and thought it was 0). ANybody know what this is?