That Fish Blog – Aquarium Advice and Information

Iodine is one of the most misunderstood, and misused, elements in the marine aquarium.  Iodine is both essential, and toxic, so understanding your aquariums needs, and proper use, is critical when using Iodine supplements.

What is Iodine?

That is a complex question. In nature, the element Iodine can take many forms, and is one of a group of elements called essential elements. Many are unstable, or play only minor roles in what is relevant to maintaining your aquarium.  The forms of Iodine that are most relevant and form the vast majority of Iodine present in the ocean are Iodide (I), and Iodate (IO₃)

Iodide is an inorganic form of Iodine. Concentrations of this form increase with depth in the ocean, and it is considered the most biologically available form of Iodine.  It is also the safest form of Iodine to use in the aquarium, and most of the Iodine supplements use this form of coral dip to kill invertebrate parasites, bacteria, and other pathogens.

What is Iodine used for in the aquarium?

Iodine is a critical element for cellular function and the transfer of nutrients within cells.  Larger organisms require Iodine for proper thyroid function, production of hormones, and regulating metabolism.  Iodine is utilized by corals for the synthesis of pigments, which allow them to adapt to varying light conditions and provide their tissue with protection from UV radiation.  Invertebrates with exoskeletons (primarily shrimp and crabs in the aquarium) incorporate iodine in to exoskeletons and require iodine for molting and forming new exoskeletons as they grow.

Testing for Iodine

As I mentioned above, Iodine is in many forms, and testing for iodine is a complex issue.  Some test kits measure “total Iodine”. Some test kits don’t tell you what exactly you are testing for at all. Quality test kits, like Salifert, will test for both Iodide and Iodate, allowing you to fully understand what your iodine landscape looks like.  Natural seawater has a total Iodine concentration of .025ppm-0.08ppm, depending on depth and location. It is important to monitor the Iodine levels in your reef, as low levels may inhibit the important biological processes that have been discussed.  Iodine is also a toxic substance, so levels above natural seawater concentrations can be toxic or fatal for invertebrates, and very high levels can kill fish and other vertebrates also.  The standard level to shoot for in the marine aquarium is generally recognized as about 0.06ppm.

Dosing Iodine

Whether you need to actually dose Iodine or not is a topic of debate amongst reef experts. The answer lies mostly in the type of system that you are running.  Iodine is present in salt mix, many additives, and most importantly many foods that you put into your tank. One of the myths that has grown in the hobby is that you HAVE to dose iodine if you’re keeping soft corals and molting invertebrates. While it is absolutely true that these animals demand Iodine, it is also true that Iodine is highly toxic if overdosed, and blindly supplementing with iodine additives can be quite dangerous. Just because you keep these animals, does not automatically require that you dose iodine.

Iodine levels are lowered or depleted by protein skimmers, chemical filtration, and biological processes.  If you are running a heavily stocked, heavily fed fish only (FO) or fish only with live rock (FOWLR) aquarium, you may find that you are maintaining natural seawater levels of iodine simply through water changes and feeding alone.  If you are running a low nutrient, coral dominated, lightly fed aquarium, you will most likely find that supplementation is required to maintain optimum Iodine levels.

There are a number of quality Iodine products available from manufacturers who specialize in marine supplements, like Brightwell Aquatics, Kent Marine, SeaChem, Red Sea and others.

Hopefully you found this helpful, keep an eye open for upcoming blogs about the roles of other supplements for marine/reef aquariums.

Thanks,

Dave

Many aquarists encounter some sort of nuisance animals at some point. Whether it is snails in freshwater or shrimp, worms or the errant troublemaking fish in saltwater, trying to remove the offender can be difficult. While there are traps galore available for sale, you can also make your own at home if you need a quick trap. This kind of trap is effective on things like Mantis Shrimp, Pistol Shrimp, freshwater snails and other small inverts and can be made from items you probably already have in your home. Read More »

Hey folks, it’s been a while! Today I’m going to give you some suggestions on creating a habitat for small South American Cichlids, but first let me tell you about some new additions to my finny friend collection. I recently bought a 4 inch Geophagus altifrons and two 5 inch Ocellaris Peacock Bass. They ended up going into my 40 breeder with my 2 to 2.5 inch Cuban Cichlid pair. After acclimating for an hour or so, they were placed into the tank.  I observed their behaviour towards the Cubans for a while, just to be sure there weren’t giong to be any problems. The bass showed no interest in attacking or devouring my little Cubans, actually it was the opposite, as the Cubans actually displayed threatening behaviour towards the bass by flaring their gills and charging at them. This went on for at least 2 days, and then I noticed that the bass would not eat any of the prepared foods that I put into the tank. I offered some trout worms and still no luck. I decided to break down and get a few small feeders, a last resort.

As the days went by I noticed that the Cubans would hide a lot and only came out for feeding, so I decided to watch them with the room lights off. The bass were hunting the Cubans! We were getting ready to move to another apartment, so I had to think fast. The wheels in my head started spinning. I moved the pair of Cubans into the 10 gallon that was holding my Largemouth Bass, and he went into the 40. He quickly assumed dominance over the Peacock Bass. I thought that maybe if the Peacocks saw the Largemouth eat that they would catch on. Again, no luck…now they’re stuck on feeders, so I’ll be hoping to trade them in one day soon.

Now on to the subject at hand, a set-up for South Americans. A tank for South Americans can range from a 10 gallon to an aquarium over a couple hundred gallons, depending on the fish you want to keep. If you’re hoping to keep fish like Peacock Bass to maturity, you’re going to need a BIG tank, but for this blog installment, I am going to talk about a 15 gallon set-up for some Dicrossus filamentosus. Known as the Lyretail Checkerboard Cichlid, males top out at 3 inches and females at 2.5 inches. This species is found along muddy shorelines with scattered leaf litter, so the decor I suggest will make them feel at home. You can furnish the tank with driftwood and maybe some small clay pots and flat stones for when the fish are ready to spawn. If you want, you can even try to add some leaves you may find in a river, stream or lake; just make sure you rinse them off really well. The last thing you want is to unleash a hellgramite or some other unwanted invader into your aquarium (yuck). I would recommend some low light plants, like java fern and anubias species tied to the driftwood, and a dark, fine sustrate for the bottom. Low light will complement the fish, too. Under bright light the blues, greens and reds on this species practically disappear. Low light plants, driftwood (which often leaches tannins) and the addition of products like Amazon Extract (blackwater) keeps this particular species looking sharp.

Once you fill the tank, check out your pH and hardness. You should aim to maintain a stable pH of 6.5 for wild fish and 7.0-7.4 for captive bred fish, with a low general hardness. The driftwood and Amazon Extract or a similar additive will help to keep the water soft. These little guys like the water warm and stable at about 80 to 82 degrees, so you’ll need a fully submersible heater for the tank.  For a 15 gallon, one in the 75 watt range with a external thermometer should do the trick. Lighting should be chosen with the plants in mind more than the fish. A small power filter pushing 75 to 100 gallons an hour should keep the environment healthy, as long as you don’t overcrowd. Stay on top of weekly water changes, about 10 percent each week. Diet for these fish can consist of any foods from flakes to frozen to live foods, like blackworms and bloodworms. I would add 4 to 5 small 1 inch fish to the tank to try to get a pair, moving the rest once a male and female pair up. Then I would add 5 rummy nose tetras and 5 neons or cardinal tetras to keep the middle of the tank active since the cichlids spend most of their time on the bottom.

I hope this was an enjoyable read for people and I hope I piqued someone’s interest in these little gems from South America. Let me know if you have any questions or if you’d like to share your own ideas for a South American set-up.

Until next time,

Jose

Peacock bass image referenced from wikipedia

With the wide range of body shapes and colors, it is hard to believe that all of the fish we call “goldfish” come from the same ancestor, a rather dull, silver/brown carp known as Carassius auratus. Almost two thousand years ago, Asian fisherman raised these fish in ponds for food, and soon the natural orange and yellow mutations of these fish caught the eye of Chinese royalty. Over time, the fish that we know as “goldfish” were selectively bred for specific traits and colors which would eventually become the varieties we see in fish stores today. Let me introduce you to some of the most popular “breeds” that have become aquarium mainstays over the past few hundred years.

Made for Outdoor Living

Comets – Perhaps the closest in appearance to the “natural” carp, Comets have longer fins than the common goldfish, and are often sold as “feeder fish”. They can be orange, white, silver, yellow or black. They get fairly large and are often sold for ponds rather than aquariums. The Sarasa Comet is a very popular variety whose coloration is a combination of pure white and deep red. Read More »

Ever play the board game “Guess Who?”? Its the one where you have to guess which character the other person is by asking questions like “Do you have a mustache?” or “Are your eyes blue?”. Sometimes identifying aquarium animals works the same way.

Banded Coral Shrimp, also known as Boxing or Boxer Shrimp, are popular for aquarists of all levels. Within this group, common names overlap, most are some variation of red-and-white-bands, two shrimp can be identical except for their antennae color and other subtle differences. These shrimp will almost always fight with another Stenopus species (and may not even tolerate their own species) so knowing which one you have is important. Read More »