What's this white fuzz in my brackish tank?

[c333davis]

The last two weeks, I've noticed a white fuzz growing on the fake plant and root decor of my brackish tank. The fuzz continues to grow, even after I've removed some of the smaller pieces of decor and wiped them down with fresh, de-chlorinated water.

The tank has been fully cycled for close to 10 months. The sg is 1.018, I change his water every 5-7 days, and my weekly water tests with the API liquid kit show 0 amon/0 nitrItes/<10 nitrAtes.

Puff's color continues to be good -- white belly, bright green head spot -- and he's eating well. I feed him 'til he has his rounded belly, then I immediately remove any food particles that he didn't consume. He seems to be breathing normally, exploring all levels of his tank, and sleeping close to the bottom at night.

I'd rather not remove and clean the larger piece of brown fake wood unless I absolutely have to. I have a new 36gal US tank that I want to start cycling soon, and I'd like to have some of his existing decor to kickstart the fishless cycling process. That said, I don't want to introduce the white fuzz into the new tank if it's harmful to Puff or the beneficial tank bacteria.

Any recommendations on further testing I should do, like checking O2 saturation in his existing water? Just wondering if that would indicate what the fuzz is or whether it's harmful. Or, regardless of what it is, should I just focus on getting rid of all traces of the white fuzz in his existing tank, and forget about using any of his existing decor or filter media to help cycle the new tank?


Image 1: Full tank shot. The fuzz is mostly on the brown fake wood at the bottom left as you face the tank.


Image 2: Closer shot of the fuzz.


Image 3: Closest shot of the fuzz.

[Pufferpunk]

Are you sure that wood wasn't meant for a reptile tank? Some decor isn't safe to be submerged like that.

[c333davis]

It's made by TopFin, specifically made as aquarium decor.
http://www.petsmart.com/product/index.j ... Id=3202479

[RTR]

It is very likely bits of uneaten food with saprophytic fungi on it. The saprophytes are generally harmless, but serve as tell-tales that there are bits of uneaten food left in the tank, and stuck by biofilms to the decor. Any rough-surfaced or nook-and-crannied decor shout be brushed with each water change. if it persists, it may be a question of the particular foods being used. Some crunchy foods do have bits blown out through the gills while grinding, or even forward through the mouth.

In small quantities, It is not a big issue, more of an aesthetic one. In larger amounts - number of such sites seen - it may indicate a change in some food. Trial and error will give you more info on that.

HTH

[c333davis]

Thanks for the insight. I took the decor out & wiped it down; last time I wiped off the fuzz while in the tank, it seemed to spread pieces - spores? - throughout the tank and left a wider field of fungus. I'll report back on my degree of success.

[RTR]

Yup, effectively that is what you did. But in and of itself that is normal tank biology. Saprophytes are 'early ' attackers of bits of dead material - in this case high-protein foods. That fuzz represents their 'fruiting bodies', pretty much their seeding for the next generation of saprophytes, which will remain dormant until they detect more fresh food available. But they are normal tank micro-inhabitants and get the solid material partly consumed, with the rest into the water column where it will be consumed bu other forms and hopefully eventually removed by our water partials. That is how the semi-closed systems we run actually operate.

It is full normal tank operation. But it is unsightly and does represent extra pollution we do not want or need. That is why I asked about the foods used - something is breaking up too much and going out the gills instead of down the throat of the fish where we want it. The nutrients are for the fish preferably, not for the water. It is also why I do not use pellets or tablets for puffers - that is the picture I saw in my tanks after such feeding. It can also occur after giving frozen foods which are not fully thawed and rinsed before feeding. Edit: It can also happen if the puff or other tank inhabitants break up the puffer poop before it gets vacuumed out.

HTH

[c333davis]

I neglected to answer about his food... I feed him thawed shrimp, crab leg, and scallops. Never any flake or pellet food. He's a terribly messy eater (as expected) and I have no doubt that he's dropping and expectorating bits that I don't see to immediately remove.

I'm curious... does the fungus feeds on diatoms? The white patches seem to be growing in diameter without the introduction of new food particles. (I know this because I didn't feed him yesterday on his "day off".)

I didn't expect total eradication after one cleaning and water change, but I guess I wanted to see no new growth. Just want to have some realistic expectations for the fungus' life cycle and possible die-off when/if I can cut off its food supply.

[RTR]

It is unlikely to impossible to eradicate the saprophytic fungi - they are normal tank inhabitants. Especially in puffer tanks where small to tiny scavengers are scarce, they are needed inhabitants. Direct bacterial digestion of tiny particles is slower. The fungus is quicker. Overall, they are better for the tank's water quality than relying on bacteria alone to digest uneaten particles.

In non-puffer tanks,such particles are consumed by snails, tiny copepods, amoeba, nematodes and/o planaria (those last two in the substrate itself more than exposed in the water column). Those critters are less numerous in puffer tanks IME. But they are ;iley present in puffer tanks in the substrate and in filters in puffer tanks still..

[c333davis]

Valuable info! I guess I'll adjust my attitude and appreciate the heads-up that the fungus gives me as well as the work that it's doing. Thanks for the help.