Jan 10, 2010

How Not To Choose Your Aquarium Fish

Yesterday I said goodbye to my two plecos. Fished them out of my tank, put them in a pail and released them into a big pond at a nearby condo development.

When I first bought the plecos, they were 3 cm each, or roughly half the length of my little finger. That was eight years ago. Now they are about 25 cm, about as long as my forearm.

I let them go, because my tank has become too small for them. I really should have done this a year or two ago. However, I've been both lazy, and a little sad to say goodbye to these guys.

Eight years ago, I had bought the plecos, because of their tank-cleaning ability (plecos will suck and eat algae right off your aquarium glass walls). They are also easy to keep in a community tank, as they are completely docile and non-aggressive towards other fish. What I didn't expect was that my plecos would live so long and grow so big.

With hindsight, my purchase of the two plecos was a classic aquarist's mistake. The fish that you see on sale at aquarium shops are usually babies and juveniles. What you need to know is the maximum adult size of that particular species. If your tank is too small for a full-grown adult specimen to be swimming around freely in it (and if you don't want the hassle of upgrading to a larger tank), then you shouldn't buy that species of fish at all.

In the wild, plecos can reach a size that you'd never see in a home aquarium. See this monstrously large specimen:


Another classic victim of the size problem is the arowana. They are highly popular among Chinese businessmen, because they are believed to bring good luck and prosperity. On the other hand, most home aquariums are too small for an adult arowana to feel comfortable in it.


Also, arowanas are very powerful jumpers. In the wild, they have been reported to jump right out of the water to catch insects and small birds on overhanging branches.

In the home context, this means that one morning you might wake up to find that your arowana has jumped right out of its tank and is lying dead on your floor.

To raise arowana properly, you would need either a custom-made and very large fish tank, or a pond. All but the most serious aquarists should stay away from trying this species.

It's only when you see an arowana in a large open water area that you will truly appreciate what a beautiful fish it is. It moves with speed, power and grace - qualities which you won't really see if the arowana is stuck in a little tank.

And here's a fascinating video, showing two arowanas breeding. Stick around to the end, to see what the male does with the eggs! It isn't eating the eggs, it's keeping them in his mouth, to protect them. Really worth watching, if you're a fish enthusiast.

16 comments:

Anonymous said...

We bought a pair of such fish to clean up our pond. They were fast & agile despite their size-they were tiny when we first had them. They compete with the resident kois for the choicest food. It is the same story all over SG, imported talent ;)

Mr Wang Says So said...

Can I ask you something about outdoor ponds?

How come some of them are so clear, while others become greenish due to algae?

Pei Pei said...

the fish that the guy catch is it real? it looks like fake wan lor!!

Anonymous said...

Same thing with dogs.

I haven seen HDB flat dwellers having big dogs, some as big as alsatians.

They need to walk their dog everyday. But they seem OK with it.

Anonymous said...

My mum had the bright idea of buying suckerfish/plecos to clean up our fish tank which was full of koi and goldfish (yes, koi and goldfish can actually co-exist). The suckerfish ended up sucking out the eyes of my mother's favourite pet goldfish - so don't assume that the suckerfish is harmless.

Anonymous said...

Our pond is serviced by pond guys. To get rid of algae, various chambers of the filteration system are cleaned regularly. A skimmer clears surface debris and UV lamps to kill "DNA in single cell algae cells"-whatever that means. We have koi pond for 30 yrs and have no problem with algae (or water quality) once the biological system of the pond is "matured".
Suckerfish are hardy, exotic looking & easy maintenance-the perfect pets ;)

-ben said...

I made the same mistake too, and had go release the Pleco into a quarry :-( A crying shame too because I was getting attached to the fella. He winks at me each time he knows I am going to give him some pleco chips.

Anyways, there's this fish that looks like a flattened tadpole. It's some kind of flat loach (probably misnamed). It uses it's entire body as a sucker and spends its life cleaning and mopping the algae off the fish tank walls. Much of its organs on its underside are visible, so you can see it's tiny heart beating. It doesn't grow bigger than a fifty-cent coin. I think I bought 2 for about $1.50 each. The fish is zero maintenance. Try your luck at the Clementi fish shops at Blk 328, within walking distance of Clementi MRT station. One of the shops closes at 10:30 PM, and the other is 24 hours (not kidding).

Hope this helps.

Anonymous said...

Releasing a non native species into the wild can result in unintended consequences. Witness the threat of Asian carp in the North American great lakes

Anonymous said...

I agree with Anon January 11, 2010 5:20 AM.

Releasing non native species is a big no- no since they can disrupt the local ecosystem. But i guess we don't even know what the native species are here in Singapore so maybe it doesn't really make much of a difference.

Mr Wang Says So said...

I released mine in an artificial pond at a condo development.

Pei Pei, nothing fake about that. Wikipedia says that plecos can reach 2 feet in length; here are some other pictures of full-grown plecos:

Link and link.

Plecos are from South America, not native to Southeast Asia ...

Anonymous said...

Plecos are clever and awesome fish on their own right. They are territorial and should be kept individually in their own tank. They should not be treated as fish to clean your tank, because they are omnivorous and will snack on your other other fish at night if they have not enough food. They also require driftwood for optimal health!

For algae in fish tanks, get catfish from the Otocinclus family 'Oto' or the Siamese Algae Eater (Not Chinese, unless you want it to grow up to 30 cm and kill your other fish) instead. Note that otocinclus are fragile and sensitive to copper.

I lost my oto when I accidentally use my old copper-based water conditioner :(

Anonymous said...

alamak, Mr Wang. You are blogging about arowanas and what not.....what happened to the old you?

Mr Wang Says So said...

What, you didn't read my "Merry Christmas and Happy New Year" post?

Mr Wang Says So said...

I actually think it would be quite interesting to keep freshwater crabs.

I've seen them at some aquariums. They're blue or orange, small and manageable, and you keep them in relatively shallow water, with rocks and driftwood for them to climb on top of.

But I don't know much about keeping crabs. I reckon it should not be too difficult to feed them; in general, I know crabs eat a lot of rubbish. :D

aw said...

mr wang dragon fish are not arowanas and vice versa

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Yes I have a question But now I am satisfy that how to choose our Aquarium fishes. But I don't want to buy this dragon fish for my Aquarium. I am afraid of when I am looking this fish.


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