Saltwater Answers: Goby, Chocolate Tang and More Do Know It Aquarium Here are some of the questions asked regarding saltwater aquarium which were answered by aquarium experts. A ghost sleeper goby 72 72

Saltwater Answers: Goby, Chocolate Tang and More

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Here are some of the questions asked regarding saltwater aquarium which were answered by aquarium experts.

Image of A ghost sleeper goby
A ghost sleeper goby

Question 1: Automatic Top-Off

I’m always interested in finding ways to simplify the maintenance of my saltwater aquarium so I have more time to spend enjoying the fish. A friend of mine mentioned that a lot of hobbyists use some sort of automatic system for lopping off evaporated fresh water in the sump, but he couldn’t elaborate much beyond that. Do you know what type of system he’s referring to? I’d like to give it a try if it’s not too complicated or expensive.
Ben Forester Chicago, Illinois


Well, there are many variations on the type of system your friend mentioned, some more complicated and expensive than others. A common design involves the use of a float valve and a separate freshwater reservoir containing a submersible pump that connects via tubing bach to the sump. The float valve is typically mounted in the sump with the float positioned at the desired water level. When evaporation causes the water level in the sump to drop below the desired level, the float valve activates the submersible pump in the reservoir, which delivers fresh water into the sump until the proper level is restored.

In some automatic top-off systems, the reservoir is positioned above the level of the sump, so the pump is unnecessary. Instead of water being actively pumped into the sump, it flows down into it under the influence of gravity whenever the float valve opens.

Question 2: Ghost Sleeper Goby Care

My local marine aquarium store has a fish for sale called the ghost sleeper goby. It is solid white with several blue dots under its eyes. Do you know if this fish has any special care requirements?
Bryn Hannah via email


The species you describe sounds like Valenciennea sexguttata, which is sometimes sold under the common name ghost sleeper goby. More commonly, I've seen it identified as the six-spot sleeper goby. If that is indeed the species you saw, it does have special requirements with respect to feeding that you should be aware of. V. sexguttata, like others of its genus, feeds by sifting through the substrate for tiny edible organisms. It can be challenging to get this and other Valenciennea species to accept nonliving foods in the aquarium, so it’s essential to provide a large, mature, deep bed of live sand for the specimen to sift through.

Having a productive refugium connected to the system is also helpful. Keep in mind, however, that in smaller systems, sleeper gobies can quickly deplete all of the microfauna from the sand bed, leaving them vulnerable to starvation if you can’t wean them onto nonliving meaty foods. Some hobbyists succeed in getting these gobies to eat prepared foods by tucking food items into the sand bed, but there are no guarantees.

Question 3: Chocolate Tang Diet

I have been keeping saltwater aquariums for a couple of years. I recently purchased a juvenile chocolate tang, which acclimated well and seems fine. I know that they are herbivores in the wild and should be fed a diet of mostly algae. I feed seaweed and fresh lettuce using a veggie clip. It seems to like both of those food items, but I’m still unsure about what I’m supposed to feed it during the day. Or do they just graze on what’s available? Could you expand on the subject of their diet?
Davis Martinec via email


Your chocolate tang is likely Acanthurus pyroferus, one of the so-called mimic tangs (juveniles of the species mimic various angelfishes of the Centropyge genus), and is primarily herbivorous, so you re generally on the right track with what you’ve been feeding. Terrestrial greens are inappropriate for marine fishes, however, so I would skip the lettuce in favor of more marine-algae-based foods.

When it comes to feeding the highly herbivorous tangs, I like to keep dried marine algae (available in sheets that you can cut or tear into appropriately sized pieces) in the tank for grazing throughout the day. A veggie clip or algae magnet is ideal for presenting the algae to the fish. I also try to vary the form of dried algae that I offer, alternating green, red, and brown varieties. Occasionally, I soak the piece of dried algae with a liquid vitamin supplement before placing it in the tank to ensure the tangs are getting proper nutrition. In addition to the dried algae, I offer a few daily feedings of other algae-based items, such asSpirulina pellets or flakes, or a frozen formulation geared specifically for herbivorous marine fishes.

Question 4: Dry Live Rock

I just received a shipment of Fiji live rock that I recently ordered, and now I’m afraid I might have been scammed. The live-rock company, which is supposed to be reputable, shipped the rock dry! I figured they’d send the pieces in some sort of container filled with salt water, but they didn’t. What are the chances that anything is left alive on these rocks?
C. J. Comes Portland, Maine


When you say “dry,” do you mean “bonedry” or “moist”? I’m inclined to think you mean the latter. Live rock is not typically shipped immersed in salt water. It’s usually shipped out of water but wrapped in moist newspaper (or some similarly absorbent material). It’s actually a good thing that they ship it this way, as the added weight of the water would probably make shipping costs for this already hefty item prohibitive for many people.

Assuming I’m correct in supposing the rock you received was kept moist, you have nothing to worry about. Many of the organisms encrusting live rock are remarkably rugged, and I think you’ll be amazed by the variety of organisms that emerge or hatch out from your rocks over the ensuing days, weeks, and months.

Question 5: Nervos Jawfish Behavior

I have had a yellowhead jawfish in quarantine for two weeks, and it is behaving very nervously. Whenever I come near the tank, it either launches straight to the surface and tries to jump out, usually banging into the tank cover in the process, or it swims downward and repeatedly bumps into the glass bottom of the tank. What can I do to get this poor thing to settle down? I’m afraid it’s going to injure itself with all this wild behavior! 
Glenn Heilman via email


Since you mention that your yellowhead jawfish (Opistognathus aurifrons) is bumping into the glass bottom of your quarantine tank, it’s probably safe to assume the tank lacks any type of substrate. That’s fairly normal in a quarantine tank, but it also means your jawfish has no way to construct a burrow to take refuge in.

When denied the safety of a burrow, it’s normal for this skittish species to behave very nervously—dashing about, trying to leap from the tank, darting for the bottom, etc. After all, getting caught out in the open where it’s vulnerable to predation can be a death sentence for a little jawfish in nature.

However, because a substrate isn’t always practical in a quarantine tank, you’ll need to make some other accommodation so the jawfish feels safe. I’ve found that sections of PVC pipe, cut into approximately 4-inch lengths, make good burrow substitutes. Place several of these around the bottom of your tank so the jawfish has some options, and it should soon claim one, settle in, and settle down.

Question 6: Frag Tank Biofilter

I have had considerable success with my 55-gallon soft-coral reef tank, so much so that I’d like to start fragging the corals and trading the frags with area aquarium stores. My plan is to set up a 20-gallon tank with an egg-crate rack and appropriate reef lighting. The system will also include a hang-on protein skimmer.

What is the best way to provide biological filtration for a small frag tank? With the way I've designed the rack, there won’t be a lot of room left for live rock in the tank, though I might be able to add a layer of live sand. Then again, most of the frag tanks I’ve seen have had bare bottoms, so maybe this isn't such a good idea. Any advice you can give would be appreciated.

Maxine Krugman Erie, Pennsylvania


First, let me congratulate you on the success of your reef system! I remember enjoying a great sense of accomplishment the first time I traded some pulsing Xenia colonies with a local dealer—even if it was just for store credit.

With respect to the biofiltration in your frag tank, I would recommend setting up a separate small sump or refugium, plumbed together with your frag tank, to hold several good pieces of live rock and/or a bed of live sand. You could put a sand bed in the frag tank itself, but with such a small system, I’d be concerned that the water movement (which should be rather brisk for the sake of the coral frags) would keep blowing the sand all over the tank.

Answers provided by the aquarium experts at Tropical Fish Hobbyist Magazine (
5 Aquarium: Saltwater Answers: Goby, Chocolate Tang and More Here are some of the questions asked regarding saltwater aquarium which were answered by aquarium experts. A ghost sleeper goby

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