Aquarium Fish Growth Myths

Eileen here. Some myths and legends are universal. Almost every country has some version of a “bigfoot” legend. Nessie is one of Scotland’s biggest celebrities. People are abducted by aliens and UFO’s are spotted in the sky around the world. What does the aquarium hobby contribute to this list?


“Fish only grow to the size of their aquarium.”

Like most of those other stories, this one likely started because people saw some truth behind it. They saw their fish grow large in relation to their aquarium, stop growing, then die. But, just like we now know that the Earth is not flat and we will not fall off the edge of it if we sail too far, we now know that the size of an aquarium does not dictate the size of a healthy adult fish.

The most common victim of this theory is the  comet goldfish, the fish often sold as very inexpensive feeder fish or won in carnival ping-pong ball toss games. People win the fish or buy them as inexpensive pets, not knowing that the tiny fish they took home should be able to become an 8-10 inch adult with a lifespan of 10 years or more if well cared for. “Goldfish bowls” are sold almost everywhere that carries fish supplies. Small aquariums – 10 gallons or under – are often sold with pictures of small fancy goldfish on the box so it is no wonder that people may be unaware of the problems they are walking into.

Keeping any animal, fish or otherwise, in a habitat that is too small for it causes a number of problems that might not be obvious at first. The fish people win at carnivals or purchase as small juveniles might be fine for a short time in a small aquarium, but as the fish grows, so does its requirements. Looking at the same situation in terms of a person instead of a fish, it becomes more obvious. An infant, for example, doesn’t require much space for his needs to be met. He can feed and exercise within the area of his nursery and regular cleanings can keep his nursery healthy. But, as the infant grows into a toddler, his needs also grow. He requires more space to exercise so his muscles develop properly. He is growing and needs more food and so produces more waste as a result that the same regular cleanings the infant received cannot control. As he grows through his life, that boy can certainly grow into a man if never let out of the nursery that he was kept in as an infant, but that man will not be as healthy as he could be. His hygiene and development will have suffered from being kept in a confined space and not allowed to flourish and develop properly and he will probably not live as long as a man whose environment has been allowed to grow with him.

The same happens when a fish is kept in a small tank. As the body of the fish grows, so does the amount of waste it produces and the food it needs. This can affect the water quality of the aquarium and lead to disease caused by high ammonia levels, high nitrite levels, low dissolved oxygen content, low pH and other incorrect parameters. Just as a person kept in a small space cannot grow properly, the fish would also physically not be able to grow to its full size. Its body and skeletal structure may be stunted by the lack of space and ability to exercise and swim as it should, but the internal organs often continue to grow at a normal rate. The internal damage this causes, in combination with water quality issues, will lead to a premature death.

While a small tank can certainly affect the size of the fish, it is not the way that we once believed. There is no internal sensor in a fish that can detect the size of its environment and adjust its growth accordingly. The fish we keep are  just as dependent upon us as small children to give them the proper care needed to keep them healthy so it is up to us to be aware of what their needs are and to do our best to make sure those needs are met throughout the fish’s life.

That Fish Place Aquariums and Fish Recap – Week of 8/17

Patty here, and welcome to our Friday recap. Lots of fun and interesting stuff crop up both worldwide and right here at TFP over a week’s time, so we’ve decided to start hooking you up with sweet updates on these kinds of things. Be sure to let us know what you think of these posts (The little thumbs up, thumbs down at the bottom), and feel free to send us some of the excellent things you’ve read in the comments or on Facebook.

This week’s Noteworthy Fish stuff

  • I know that a little romancing can go a long way, but who knew that a little Barry White could push a cold fish into a passionate frenzy?! At the Sea Life London Aquarium, they’re doing what they can to set the mood for poor Zorro the Zebra Shark to woo the ladies. Good luck, little guy, everybody needs a little love!
  • We already know the benefits of having live plants in the home aquarium, but it never hurts to say it again. I personally don’t think enough can be said about the benefits, and this article breaks it down in easy terms just to push the issue a little more. I mean, how would you like it if you were suddenly dumped in a bubble with only plastic trees and flowers? It would be like living on a Hollywood movie set!
  • How lucky is this guy? I can’t say I don’t envy him! This beautiful behemoth seems to be just as fascinated by the diver as the diver is by him, so whatever he is doing to draw its attention is working, just watch out for flailing fins and tails. The amazing shots are definitely share-worthy. Sure, these are mammals and not fish, but still….
  • MACNA 21 is just a few short weeks away! The Marine & Aquarium Conference of North America (MACNA XXI) is being held in Atlantic City, NJ September 25-27, 2009. This is one of the biggest annual events for people in the industry and hobbyists alike. There are loads of exhibitors, awesome speakers scheduled raffles and tons of other fun to be had, drop the family at the shore and head to the Sheraton! Check out the homepage for full details! *Shameless plug* Your favorite Aquarium Supply store will be there too, so stop by and say hi to Dave.
  • Meanwhile, back at That Fish Place the most exciting project going on is the newly constructed Coral Propagation room. The room will soon be slowly populated with lots captive grown frags and in house cultured frags for future sale both in the retail store and online!
  • Our 700 Display got bright new bulbs this week and a few new fish additions. If you look closely at the rock it would appear that we’ve had a spawning , as there are numerous tiny new colonies of either Pocillopora or Seriatopora appearing all over the place! Stay tuned, they have to grow out a little to be sure.
  • The results of our first cross-Facebook/Fish Catalog photo contest are in, and Michael S. from McConnellsburg, PA is the winner with this sweet pic of a Black Misbar and a Derasa Clam. Michael will receive a $100 gift card, and have his photo featured in the Fall fish catalog. Check out Michael’s picture here, and if you’re interested in entering for the Winter Fish Catalog, send your high-res photo to
  • Cool new stuff at That Fish Place this week

  • Spanish ShawlYou can see where the Spanish Shawl Nudibranch gets its name, flamenco anyone? Very cool but they are specialized feeders like many other nudis!
  • Chestnut Cowries eat algae when their little, but may develop a taste for sponges and softies on the side as they mature, so keep that in mind!
  • This Hawaiian Cultured Blue Maxima is A-mazing!
  • Two species of microrasboras, very cute, very tiny, maybe worth a small species tank, but probably not fitting for the average community right now due to their small size.
  • Though I’m not nuts about crazy hybrid cichlids, this Red Dragon Flowerhorn is pretty eye catching.
  • Two sweet War Coral Frags…Get them while they’re here!
  • And from ORA, Extreme Misbar Ocellaris! No two are alike!
  • Just a sampling, come see us and check out these and tons of other cool stuff!

    Until next time,


    Long Live the Queen Angel in Declining Caribbean Reefs?

    Melissa here. I recently read an interesting article (sadly, one of many) on the decline of Florida reefs.  The prognosis for the future of many Florida and Carribbean reefs is not looking good, especially if steps are not taken soon to stop the forces that are having such a negative impact on these environments. The reefs off the coast of Florida’s keys are in real danger, and according to this report, there has been a significant decline of both reefs and some fish populations in just the last 10 years. Snapper and grouper populations in particular have declined according to the article, and it is estimated that they are below sustainability levels. While I have been to Florida several times, I have yet to scuba dive there. I have been told by friends that it’s beautiful, and that wild queen angels (my favorite fish!) swim freely on these reefs. This article doesn’t address the Queen Angel population, but with their habitat being in trouble I wonder and worry about the impact on them over the next decade and beyond. I don’t know about you, but being an avid Queen Angelfish lover, I would love to take a trip to the Keys so I can take in the beauty of these reefs before it is too late. It may be sooner than we all think that this and other majestic species will only rarely be able to be observed, except in a captive aquarium environment. Feel free to let any thoughts you may have about the declining reefs and fish. Here is a link to the article if you want to read more:

    Feeding Canned and Live Insects to Marine and Freshwater Fishes – Part 1

    Hello, Frank Indiviglio here.  Anyone with an outdoor swimming pool is aware of the vast numbers of insects that continually crawl into or alight upon the water.  If you now consider how many billions of terrestrial insects find their way into the world’s fresh and marine waters each day, you will quickly realize that fishes have ample opportunity to consume a food item that is not usually included in captive diets (and lets not forget about the millions of aquatic insect species).  Small wonder that earthworms, crickets and waxworms are among the most effective fishing baits known.

    An Overlooked Resource

    However, while the sale of live and canned insects to reptile owners has long been a booming business, aquarists have largely disregarded insects as a food source for fishes.  Even well-known insect specialists such as African butterfly fishes (please see photo), mudskippers and archer fishes are rarely provided with the invertebrate-rich diets they favor.


    My Introduction to Insects as Fish Food

    I first became aware of just how much fishes favored insects quite by accident.  As a youth I constantly experimented with mixed species “shoreline” type aqua-terrariums…green treefrogs living on branches above guppies, bronze frogs with pumpkinseed sunfishes and so on. 

     I noticed that crickets which fell into the water were set upon ravenously by whatever fishes happened to be nearby.  Dead, water-softened crickets elicited a feeding frenzy among even the most “peaceful” of fish species, such as guppies, Cory cats, platys and swordtails.


    Using Live and Canned Insects

    I soon found insects to be eagerly accepted by many typical (and untypical!) aquarium fishes, including freshwater, marine and brackish species.  I continue to use substantial numbers of insects as food for a wide variety of fishes, and believe that the vigor, color and health of many has benefitted as a result.  Increased feedings of insects and similar foods may also be useful in bringing certain freshwater species into breeding condition.

      Canned invertebrates offer a convenient method of providing your fishes with valuable dietary variety.  Next time we’ll take a look at their role in fishkeeping and some other examples of insect-feeding among wild fishes.  Until then, please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.


    Further Reading

    The archer fish feeds almost entirely upon terrestrial insects, knocking them from vegetation with well-aimed jets of water.  By specializing so, it is able to exploit a unique food source in a habitat teeming with competing species.  The Friends of the National Zoo has posted information on their care in the zoo and natural history at

    Please see also the following article on our blog – Archerfish: Aquatic snipers for husbandry advice.

    Image refereneced from Wikipedia and originally posted by Toniher.

    Novelty vs. Cruelty: The Ethics of Dyed or Tattooed Aquarium Fish

    A recent news article brought an old debate back to our attention here at That Fish Place – how far is too far to go to get a “unique” fish for your aquarium? The article discusses the recent trend in the Chinese aquarium market for tattooed fish believed to bring luck and prosperity to their owners. The fish in the article are Parrotfish, a fish that is already considered a hybrid of other South and Central American cichlids. These fish are being laser-tattooed with designs or Chinese characters like “luck”, “happiness”, or “May your business boom,” the article states. This tattooing is done much like that on a person and can severely damage the scales and body of the fish. I’ve seen and heard of other fish in the international aquarium trade that have been tattooed in a similar way, like Giant Gouramis and mollies.

    Similarly, “Jelly Bean Parrots” have also been available in the trade. These fish are usually brightly colored in shades of green, blue, pink or purple – a process often done by first dipping the fish in an acidic solution for a short time to remove their protective slime coating, then dipping them in a dye solution. This process is not permanent and usually fades over a few months, and the mortality rates of these fish during the dying process is very high. Some other fish like tetras (some are often known as “Stained Glass Tetras” or “Painted Glass Tetras”) are also dyed in a similar way or injected with dyes to give them their bright, artificial colors.

    Here at That Fish Place, we make every effort to avoid carrying fish that are the product of unethical practices like the dying or tattooing of fish but unfortunately where there is a demand, there will still be a supply in some areas. While some fish that seem unbelievably brightly colored are the product of selective breeding and are completely healthy, others have been through a lot to get that way. As a general rule: if you see a fish that doesn’t appear to be a “natural” color for that type of fish or the color seems to good to be true, ask if it is! Practices like this will only stop if we, as ethical aquarists, ban together to speak against them.,27574,25926147-13762,00.html