HELP!!! Tiny white 'bugs'!!??

[Azsunluvr]

I just thought I was freaking out.....
3 weeks ago, I lost 3 fish within a week of each other, with no outward manifestation. One evening they're not eating, the next day they're lethargic, that night they're dead. I actually was able to keep the midnight angel alive for a couple days in the hospital tank with copper and anti-biotic.

Things seemed to have calmed down, then two days ago I saw what appeared to be a light snow storm of very tiny white "things" floating all over the aquarium. Kind of like the dust you see in the air when sunlight streams through a slit in a curtain. Closer inspection revealed that some of these little white things were stuck to the inside of the acrylic. Worse yet, it wasn't just current moving these things around, there were crawling! Egads!! What the hell is that? Whatever it is, it is too small to make out any shape, ie head, tail, legs etc, just looks like a spec of dust.

My tank is 300 gallon, closed system with 2 LG4, 2 Ocean Clear 40, 30 watts UV running at max kill rate. This is aggressive fish only, with no inverts, no LS or LR. Tank has been running now for 11 months. Am-0, No2- Unknown (Can't seem to get a result), No3- 20, SG-typically 1.020. However, currently it is 1.014, on the way to 1.009 to try and kill these little buggers. Currently I have 10 fish in the 3-5 inch range which look good at this point.
I added chelated copper (first time) to 1.5 mg/L. Was going add more, but it seemed to be getting worse, so I'm heading down the path of hyposalinity.

When I was doing the water change to drop the SG, the water from the sterilizer comes in from a separate line. When the water level was low, this incoming water was dropping in from 3-4 inches above the tank water level creating bubbles. These little white things were swarming under this water fall.

Now that the SG is down a bit, there does appear to be fewer of these things. Maybe they just go to bed to psyche me out

Fish include: 5" Imperator (3/4 through change), 4" spiny puffer, 4" Yellow tang, 4" & 2" blue tang, 3" picasso trigger, 2" valentini puffer, 2" blue damsel, 3" tomato clown, 3" potters angel. I lost my radiatta lion, flame angel and the midnight angel

Does anyone have any idea what these things might be? Am I screwing up by going hyposalinity? I'm lost, I don't know what else to do.

Needin' help in Arizona!

[ReefNutPA]

Woah!!! Slow down..... you've already added copper to your tank and are dropping the SG into hyposalinity range to deal with a problem which you have no idea what it is. My tank is crawling with hundreds of little tiny "bugs" and I wish I had hundreds more! Since you have no LR or LS, I'm not sure what the "bugs" are that you are referring to.... but in my opinion, you should try to figure out what happened that you lost 3 fish before you start adding copper to such a large tank (which will be absorbed by the substrate and any other decorations you have in the tank and remain in the tank for a loooong time). The only thing I can think of is your selection of fish, even though you have a very large tank, is questionable. Yellow Tangs, Flame Angels, Potter's Angels, Clowns, Blue tangs are not aggressive fish (even though your post says "aggressive fish only with no LR or LS). I'm not too sure that many angels & tangs in a tank with truly aggressive fish like Lions, Puffers & Triggers is an ideal situation. Just my opinion though. I'd possibly try to take a pic of these "bugs" and post them on Dr. Ron's board and see if he can ID them for 'ya. If they aren't harmful....you're doing your tank more harm than good by adding copper and going hyposalinity.

Tom

[billsreef]

Tom is right, you need to slow down. Before throwing chemicals and other treatments at the fish you need to figure out what the problem is. After determining the problem then you can come up with a treatment for that specific problem.

It is very rare to have fish parasites swarming in the water column in quantities that you will be able to see like that. Also anything large enough to be seen by the naked eye will also be quite evident on the fish. The most likely ID for those "bugs" is harmless copepods. It is not unusual to find copepods finding thier way into a FO tank, they also tend to be unaffected by copper. Find a magnifying glass and take a close look. They typically have a forked "tail" and sometimes a pair of egg sacs that will make them look they have two segments.

Your water parameters look good, but I have a couple of questions for you that will help us determine what happened.

When were the fish (the ones that died) introduced to the tank?

Any recent additions or changes made to the tank?

BTW one possible contributing factor with the angels is too many in the same tank. Even though a 300 gallon is large by human standards is quite small by fish standards. Next time you go diving find an angelfish, tang, or trigger and follow it around, then think about how much terrertory it covered and compare that to your tank...all of a sudden that 300 gallons is going to seem quite small :eek2:

Pygmy angels are also difficult to find in truly good shape. Several, especially the flame, are known for doing great for about 2 months and than just dropping dead :( Radiata lions are also one of the more difficult fish to keep alive.