6. "It will only grow to the size of its tank!"
Ok, so this applies more to goldfish, but I have heard it about other fish too, bettas included. It frustrates me particularly because people use it as a reason to keep cramming comets (stunning fish which should grow to more than a foot long) into gallon bowls.
No, fish do not grow to the size of their tank. It can be an influencing factor (you may notice fish grow slightly bigger in larger quarters) but it isn't what keeps a fish with the genetic potential to be 14 inches at a measly three inches.
The reason most fish stay tiny in tiny tanks is because there is more ammonia in a tiny tank. Poor water quality, just like poor nutrition and environment for humans, will stunt a fish's growth. Poor water quality is generally more prevalent in small tanks because they are harder to keep clean and there is a smaller volume of water diluting the waste. If you kept a comet in a tiny tank but did massive water changes all the time, it would still grow. My own goldfish is a case in point - we had him in a small tank, but he kept growing because we kept the water clean. The reverse is also true - keep a fish in a huge tank but let the water get awful and the fish will not grow.
This lack of information generally leads to comments like this:
7. "You shouldn't buy one of those, they die really easily".
Now, I could understand if people said this about orange-eyed blue tiger shrimp, discus or French Angelfish (the saltwater ones) but what you actually hear it about are goldfish and bettas (seriously, has any other fish been so abused?).
They are two of the hardiest fish in existence. They are extremely easy to care for - as long as you are doing it right. Any animal will get sick or die if you don't care for it properly. Don't blame the animal for your lack of care, whether through ignorance or deliberate neglect.
Of course, one of the most common causes of fish dying really quickly is New Tank Syndrome, from people putting a fish in the tank and causing it to cycle. This generally rises out of the following myth:
8. "Run your tank for 24/48 hours, then it will be ready for fish."
I'm not actually sure how this came about, but I suppose it must just be a perversion of the actual cycling process.
What happens if you run your tank for 24 hours? Well, it gives you a chance to make sure your filter is working and that your heater is at the right temperature, but it does diddly-squat to prevent NTS. Without a source of ammonia in the tank, nitrifying bacteria will not start to build up in the filter. Without them, the filter really isn't doing much in terms of biological filtration, although it will still be useful for mechanical filtration. Even with ammonia in the tank, 24 hours won't do anything. *Insert explanation of the nitrogen cycle here*.
Another petshop gem that makes me wince is this:
9. "You can have one inch/cm of fish per gallon/litre".
I agree. This rule is wonderful. If you are stocking neon tetras in a 20+ gallon tank, anyway.
For any fish other than that, this rule is not good.
First, you have your dramatic examples, like a 10-inch oscar in a ten gallon tank. Most people are thankfully not so short-sighted as to make this kind of mistake, however (except with goldfish).
Then you have the less extreme examples. For instance, 2-3 glofish is a total of 4-6 inches, right? So you could probably fit those in a 5 gallon, right? Well, yes, they would fit and they wouldn't ever grow out of it, but it doesn't take into account several things:
- schooling needs. Most small fish are schoolers and need groups of 6 or more to avoid stress (stress = compromised immune system = sickness).
- territorial needs. Kissing gouramis get about 4 inches long, but you wouldn't stick two in an 8 gallon tank - they would tear each other apart. Dwarf puffers are what, an inch? Stick two of them in a two gallon tank and they will murder each other.
- activity levels. Fish like danios are incredibly active. They love to zoom. They need to zoom. Smaller spaces = increased stress. 5 gallons doesn't give them zoom-room.
- bio-load. Guppies are smaller than bettas, but they poop more. I would stock a ten gallon with 6 female bettas, but I'd only have 4 guppies.
At the other end of the scale, you have things like kuhli loaches. These get 4 inches long, so you could only keep 5 in a ten gallon by this rule. But they have small bioloads, so you could easily keep ten in a 20 gallon no problem.
That particular myth has a lot to answer for - many people use it to 'prove' that their tank isn't overstocked. The final one (also a question of stocking) that drives me batty is this:
10. "I need an algae eater/snail/catfish/bottom feeder to keep my tank clean!"
Poor little algae eaters. Touted by petshops as a kind of miracle for tank maintenance, they are in fact anything but.
Firstly, most algae eaters only eat some types of algae. Many will prefer to snack on actual fish food instead, and some will even prefer your fish (yes, I'm talking about you, Chinese Algae Eaters). Those that will eat almost anything (Siamese Algae Eaters - don't get them confused) get a good six inches long and won't fit in the average tank. So no, an algae eater isn't a solution to algae.
Secondly, they don't eat poo. Many fish will put poo in their mouths by mistake; many fish will also spit it right back out again.
Thirdly, "tank cleaners" create as much waste as they eat, if not more. So, whilst they may clean up visible stuff like uneaten food, they aren't going to help with the invisible stuff, and as any fish keeper can tell you, that's the deadly stuff.
Fourthly, just because it is an algae eater/bottom feeder, doesn't mean it isn't a fish. Many people seem to view them as less than a fish, which baffles me. As a consequence, they don't take into account the fish's needs (such as common plecos needing huge tanks, and cories needing schools).
So there you have it. Ten myths that make me cringe, myths that force me to bite my tongue to avoid screaming (and possibly biting the speaker instead). And the answers that I wish I'd had the foresight or the calmness to say at the time, or have since rehearsed so I can spring them on the unwary novice. I hope they can help you, or that you can at least find comfort in knowing that other people, too, have felt this pain. :)
Feel free to disagree with me.