I have 2 pink convicts and 2 firemouths. One of the pink convicts was rubbing it sides on the rocks on the bottom of the tank. The next morning it was dead. It appears normal (no bloated belly or visible marks). I checked the water conditions and they was fine. I used the api master test kit. We also had 2 pictus catfish for about 2 weeks and 3 days ago they both died over night. The pink convict and the 2 firemouth used to be very active. Now they just hid in the plastic plants together. We notice the one of the firemouth has little white specks on it. We tried to look on the pink convict but it is pretty white so we can't tell. Does anyone has any suggestions as to what is wrong?