My Yellowtail Blue Damsel won't eat flake food. He only eats algae off of rocks. Can he live on green algae?

Question

I am cycling a marine tank with live rock and a damsel. I've had a green algae bloom, and since then my damsel will not eat the flake food. Will he be ok? Should I try a different type of food?

Thanks for the help already! Let me add some more info. Ammonia, nitrites and nitrates are all still testing 0. Specific Gravity is 1.022. PH has been between 8.2 and 8.3. I have only used RO water in the tank. I did a very small partial water change (10%) at 2 weeks. The tank has only been set up for about 2.5 weeks now.

I have only been feeding my damsel a flake of food the size of his eye 1 time/day. That is what the people at the LFS suggested.

Is it OK to add snails now? My LFS told me not to add anything for a few more weeks because the cycle may not be done yet. All the books I have read suggest something different. I haven't seen an ammonia spike, but they suggested it may have been very small due to the live rock.

Sorry for rambling!!! Thanks again!

Answer 1

Damsels need a variety of food in their diets, so I would continue to offer some flakes, but also offer some frozen foods (enriched brine shrimp, marine cuisine, emerald entree, mysis shrimp, etc.). Just be sure you're not overfeeding him. And they should have some algae in their diets, but if there's too much growing on the rock, he may not be able to keep it under control by himself.

My first concern about the damsel is that it may have stopped eating if the ammonia or nitrite was too high in your tank. A problem with nutrients may also be responsible for the algae bloom. And if the algae is taking in enough nutrients, they may no longer be showing up on your water tests. But if he's happy eating the algae (or small inverts in athe algae), at least he is eating.

If your water is testing okay for ammonia, nitrites, and nitrates, it may be time to add a few snails and hermit crabs to try and get the algae under control, but keep an eye on your water parameters - if the algae has been taking in excess nutrients, once the alge is being removed, the nutrient levels in the tank may go up.


ADDITION: If you have a good quantity of live rock, your tank may be cycled already. Your ammonia and nitrite results would seem to indicate this. At any rate, if you're getting algae on the rocks already, it must be getting nutrients form something, and RO water wouldn't have nitrate or phosphate, which is what the algae would need to grow.

You might want to try a different food for the damsel, such as one of the frozen foods like Marine Cuisine or Emerald Entree. I would try feeding him a little more than the equivalent of one flake a day - it's hard to judge how much without knowing the size of your fish, but the tank needs to have a source of ammonia (your fish's waste) for cycling to continue. If the fish produces minimal ammonia, the "extra" bacteria will die off, then spike again as you add fish later. This isn't to say you should overfeed, either, just give him what he can eat in about 2 minutes twice a day.

If you increase the feeding and still don't get an ammonia or nitrite spike, I think you'd be safe to start adding cleaners (snails, hermit crabs) to your tank.

Answer 2

i would add some mysis shrimp, or even a freeze dried food. brine is ok as long as you dont feed it more than half the time, brine are not very nutritious. as for the algae bloom , use RO water availbale at walmart or target. and 10% weekly water changes and cut diwn on feeding, try pellet or frozen foods as well, flake is pretty wasteful. a few snails as well, about 1 for every 3-5 gallons is good.