Cleath - I was thinking the same thing, that the goby ingested some cyano and got sick from it.
Yes, I use RO/DI water. It is a 5 stage - Sediment, 2x Carbon, Membrane, DI. I have two inline TDS meters on it monitoring its performance. I have a 98% TDS rejection rate through the membrane and a 100% after the DI. I replaced the filters and the resin about two weeks ago. Before replacement I was getting 1 ppm TDS out of the DI stage
I have a 3600 GPH dart on a closed loop with 12" (1ft) of head providing current. I have a couple of 1" SeaSwirls that I will be hooking up this weekend, but right now it is just the 3600 GPH flowing through a 1.5" return. The current is so strong that there is a patch on the end of the aquarium where the sand has blown off to the point exposing the glass. Yet, I still have cyano on the sand sitting right next to that exposed glass. I have experienced this before in my previous aquarium, where there was obviously strong current (3x Tunze 6100s plus 2400 GPH from a return on a 6'x3'x20" aquarium) but the Cyano still grew. The increase current solution has never worked for me.
I have been negligent on water changes, I will admit. I will be starting them up again once my salt that I ordered finally arrives.
I didn't realize O2 tests where inexpensive. I will shop around and see what I can find.
I will also try the flake food solution. I was also considering getting some selcon and garlic to soak it in to boost immune systems. Hopefully my fish don't get to upset that their favorite brine and mysis combination has changed!
I run Phosban in a phosban reactor to remove phosphates. Phosphates are untraceable on my Salifert test kit.
Also, my drain from my tank runs directly into my 10" diameter 40" tall protien skimmer with two mesh-modded aquabee 2000/1 recirculation pumps (DIY) at a rate of 600 GPH. I'm only pushing 20 LPM though the pumps at the moment, but I have just ordered a new air pump that will bump that up to 40 LPM. It's a heck of a skimmer.
Thanks for the in-depth reply!
odyssey1 - The Goby is a bit lethargic, but not terribly or much more noticeably that normal. It is hollow bellied and pale, but it's fins and scales are in fine condition and it eats like it always has. There are also no yellowish or darker nodules appearing on the eyes or body, and it is not deformed. I'm not sure if I would say that the blotches on its skin are ulcers. They are only around the throat and appear to be a result of a growth in its throat (seen in picture 2) that has swollen to the point of being visible through the pale skin.
In light of this, would you still lean toward Tuberculosis and/or recomend the same treatment?
alprazo That may be a bruise, but it looks like it is the growth in its throat becoming visible through its pale skin. Does this sound like the fatal outward growth you mentioned?
I'll go pick up some Minocycline and Kanamycin.
Something else I should mention. I was using vinegar to spike my Kalkwasser. I seem to have added too much and had a bacteria bloom as a result of this, which clouded up my water. All of my parameters were fine during and after this. I have since ceased using it until my Goby looks better. Can anybody think of a connection there?
Thank you all for your help!