Planted 20 gallon long built and fishless cycled in June/July. Nitrates never higher than 40, Ammonia and Nitrite at 0 with no spikes. Ph usually in the 7.6-7.8 range. Heater set to 83, but since the weather has gotten colder the thermometer on the opposite side of the tank from the heater reads 75.5-78. 1 plakat betta, several MTS and Nerite snails. The betta came from the Co-Op, and I have had him for around 4 months. The only recent change is that I added water sprite from the Co-Op, which he loves and is often resting in. I bought 10 kuhli loaches a month ago but they are quarantining in a separate tank in a separate room. He has developed white dots on both of his eyes, as seen in the picture (he was sleeping, but I turned on his light just now to snap this picture.) His activity has decreased, although he still swims around all of his tank. His appetite seems to have dropped too. When the dots developed I watched for a few days, read about cloudy eye, and then treated with Maracyn. No change in appearance or behavior. He is now on day four of the 5 day Paracleanse schedule, with still no improvement. What should my next steps be?