low dissolved-nutrient levels, such as reef tanks dedicated to fussy SPS (
small-polyped stony) corals, may not be able to sustain them as well without iodine
supplementation. Again, this is just a theory and I have no scientific evidence to
either support or refute it, but it does provide food for thought, anyway.
Since your pulsing xenias are doing just fine without supplementation,
I would recommend leaving well enough alone for now. You can always
begin supplementation in the future if it seems appropriate, e.g., if the
corals slow or cease their pulsing or appear less robust.
Green Wolf Eel Care
My local fish store has a fish called a green wolf eel on
display, and I’m interested in buying it for my 75-gallon
fish-only tank. Can you give me any information on
this species and how to care for it properly?
Gwendolyn Kopp
Henderson, Nevada
The fish you saw was probably Congrogadus subducens (or
a closely related species), which is commonly called the green
wolf eel. Other common names for it include the carpet eel
blenny and the eared blenny. Interestingly, C. subducens is
actually a member of the family Pseudochromidae—the dottybacks—and
not, as its various common names suggest, a true eel or a blenny.
C. subducens reaches approximately 18 inches in length, so I would
consider your 75-gallon tank to be the minimum housing for one. I would
recommend a significantly larger tank if you plan to keep this species with
other fishes. The reason is that C. subducens is a voracious eater and
will make a meal of any fish or crustacean small enough to be swallowed.
Q
A
Green wolf eels Congrogadus subducens can be kept with other
large, aggressive fish in very big tanks.
Gary Lange
Hence, suitable tankmates are limited to other big, aggressive fishes, such as
larger surgeonfishes, wrasses, triggerfishes, and angelfishes, most of which
will ultimately grow too large for your 75-gallon tank.
Since its natural diet consists primarily of crustaceans and fish, try to
replicate this with its captive diet—offering meaty food items of marine
origin (e.g., shrimp, krill, crab, chopped fish, and frozen silversides).
Also, be sure to arrange the rockwork in your tank in such a manner that
provides ample hiding places for the wolf eel. A suitably sized section of
PVC pipe in which the specimen can take refuge will be appreciated as well.
Q
Reef Lighting
I have a 120-gallon reef tank, and my corals have been
spreading like crazy. All of my equipment is overkill, and I
have been propagating corals to trade in for store credit, which
pays for everything but electricity. The tank has 180 to 200 pounds of live
rock and about 4 to 6 inches of live sand. The lighting system has two 250-
watt metal halides and two 65-watt fluorescents. I have been propagating
Xenia, star polyps (which burn my other corals), and various button polyps.
I also just started fragging my Stylophora, Montipora, and Acropora.
I have two questions. First, because my Xenia and star polyps spread so
fast, I am running out of room. I’m thinking of starting up another tank that
runs off my main tank. If I purchase a 4-foot, 33-gallon tank that is only
12 inches high, I could light it with a 4-foot, 260-watt compact fluorescent
fixture from an old tank. Will that be strong enough if my light is close
to the water and I put my high-light corals near the top and the low-light
corals near the bottom? Will they still grow like they do in my main tank?
Second, my fish are as important to me as my corals. I have it stocked with
a good variety, and they all get along great, although I have three fish that
will outgrow the tank if I don’t do something soon. I have a blue-chin and
Niger trigger, and I would love to add a sargassum trigger and my favorite, a
Naso vlamingii. The vlamingii is why I am thinking of getting a much bigger
tank—not for more space for corals, but for more room for my fish to swim.
I am thinking of a 6-foot, 300-gallon tank that is 36 inches wide. If I keep
the light that I have now over my live rock and corals (I will also add more
live rock to my frag tank for filtration), will that throw off the watts-per-gallon ratio I need for my corals to flourish like they are now, or am I going
to have to add another fixture (hopefully not)?
I am almost halfway there in store credit to purchase the tank. Your input
would be greatly appreciated. I learn a lot from your “Saltwater Q&A”
section and love the whole magazine.
Marty O’Rourke
via email
22 www.tfhmagazine.com
Rather than guesstimate whether your 260-watt compact
fluorescent fixture will provide sufficient light for your proposed
frag tank, I would recommend that you invest in a modest
light meter and take some light-intensity measurements for
October 2010
