Common Misconceptions About Keeping Aquariums

People have been keeping fish for hundreds of years, but only within the past 50 years or so have they become so common. It is also during this time that many misconceptions have come to the surface. Most of the time these originated because of a lack of knowledge, but as we experimented and technology got better, we got a better understanding of fish. But this initial information (or sometimes intentional misinformation) is still around, and the vast majority of people who keep fish think at least one of these things is true.


  • You need a cleaner fish.
    "Cleaner fish" is a harmful term, because it implies that a fish will clean your aquarium in some way. However, it does not specify what "cleaning" means and most people assume that there is a fish that will help clean their water. Most people don’t put much more thought into it than that, but others assume that the fish must eat the poop of other fish and leftover food at the bottom of the tank.
    Not only will no fish eat another fishes feces, but all fish themselves create feces and contribute to making a tank dirty. And if there is food leftover on the bottom of the tank after you feed your fish, you are overfeeding them and need to feed less. Buying a fish to eat the leftovers will only make problems WORSE by having yet another waste source in the tank. Another thing that people don’t realize is that a fish creates ammonia as they breath. So they don’t need to pass waste at all to make your tank dirty. Simply by EXISTING they make your tank dirty! So no, a “cleaner fish” will not keep your tank clean and you do not need one. Sure, some species of algae eaters will eat algae but no one species tackles all types of algae and they may leave the algae in your tank alone, even if you starve them. They are only designed to eat certain algae. YOU are what will clean your fish tank, not a cleaner fish!
  • Fish grow to the size of their tank.
    Not only does this not always happen, but when it does happen it is the equivalent to underfeeding your dog so it is stunted and dies young. Sometimes, when a fish is put into a tank that is too small, it becomes stunted. But this is not through some miracle ability to realize it’s environment is too small and telling itself “Ok organs, don’t grow too big ok! But live a nice healthy life ok?” The reality is quite different. When a fish is exposed to a stressor, it’s body reacts in two ways to overcome the stress. First involves the endocrine system. The response of the endocrine system is to gather the engery to overcome the stressor. The second way is through the fishes metabolic system, where it tries to reestablish homeostasis.
  • In the wild a fish is exposed to stress temporarily. (Heat waves, cold snaps, lack of food, overcrowding, predation, etc.) After the stress passes, the fish is able to go back to living normally. But in an aquarium (such as one that is too small, or dirty, too bright, fed improper or bad foods, or has aggressive tanks mates) these stressors are long-term and often permanent. This then physically prevents the fish from developing as it should and creates a stunted, unhealthy, short lived animal. You NEVER want to stunt your fish.
  • You should buy feeder fish to put in a new tank. This came about from when people did not know what the nitrogen cycle was, or at least they did not know that it occurred in aquariums. Back in the infancy of fishkeeping, people knew that the initial set up of a tank usually resulted in fish dying. They did not know quite why, but they chose hardy fish to put into the tank initially so they were less likely to die off. But now we know that the reason behind this is because there are no beneficial bacteria in large enough numbers to break down waste. These bacteria live in your filter pad (or sponge) and are vital for a successful tank. SINCE we now know this there is 100% no reason to throw hardy fish into a tank and cross our fingers. That death is 100% avoidable by cycling the tank BEFORE adding fish in any tank.  This concept, that some fish are expendable and you should kill them so you can then own other fish (which is a luxury) is an extremely selfish type of thought and needs to be abolished. Animals are not here to please us. The goal of fishkeeping should not be to please ourselves at all costs, but to keep fish as happy and healthy in captivity as possible. 
  • You can keep tetras/corydoras/barbs in groups of 2-3. This is another myth formed out of human wants trumping an animals needs. An often overlooked part of fishkeeping is examining a fishes psychological needs. All fish interact with other fish in some way. Sometimes this means schooling with others of the same species, sometimes it means living in a mated pair, and other times it means only coming together to mate and trying to avoid other fish at all costs. So to keep fish in captivity we MUST take this into consideration. YES it limits how many species can be mixed in certain volumes of water. Boo-freakin-hoo. A 10 gallon is only large enough for one species of fish, with rare exceptions. You see many fish, in fact most fish sold in stores, are schooling. This means that they live in large groups to avoid predators in the wild. These group sizes vary, but common fish like neon tetras are often observed in groups of several hundred. What makes you think keeping 2 or 3 is even remotely close to recreating that? The larger the school the better, and the larger the tank the better. Yes, neons can technically fit into a 10 gallon. But wouldn’t they be happier and healthier in a school twice the size of what you can fit in a 10 gallon and in a 20 or 30 gallon?
  • Your filter cleans your water for you. People are often uneducated about fish when they start out, and assume that a filter makes the tank a sort of closed system. This could not be further from the truth! A filter is our meager attempt to recreate the way a wild ecosystem is able to sustain aquatic life in our living room. In the wild there are tons and tons of beneficial bacterial to break down waste, fresh water is continuously brought in (By rivers, underground, or through rainwater), plants break down waste as well, and all around everything works perfectly in an extremely intricate balance to maintain life in the wild. In our aquariums we have a tiny half-assed version of this going on. Our filters are small, our filter media is often inefficient, and we have this nasty habit of overcrowding our aquariums.
  • Goldfish can go in bowls. I go into this and other goldfish specific myths here. Goldfish, when properly cared for, get between 5 and 24” and need anywhere between 40 and 100 gallons of water to survive to their natural lifespan of 15-20 years. They are in no way suited for small aquariums at any point, and should always be kept together with other goldfish. This myth seems to have arisen from companies trying to sell small aquariums. The only people who would be guaranteed to not know anything about fish are those who do not keep them, and who better than children to deceive. So they market these bowls as something perfect for kids and well-meaning parents eat it up. Unfortunately, it is also fueled by the view of animals as commodities rather than living creatures who demand respect.
  • Start out with a small tank and see how it goes. If they survive, then you can move onto a big tank. I see this one at work all the time. It’s simple: Smaller tanks have less water to dilute waste and limit the amount of fish you can have. They are cleaned out more often because of this, and will not allow you to get over half of the fish in any pet store. Do yourself and the fish a favor, start out with a tank no smaller than 20 gallons!  By getting a small tank first you are setting yourself up for disaster.
  1. sad-monsters reblogged this from shatterwitch
  2. dirtybrian reblogged this from iantojonesthebetta
  3. sci-bear reblogged this from scalestails
  4. ghostjams reblogged this from spacexxcowboy
  5. spacexxcowboy reblogged this from scalestails
  6. cicadachirps reblogged this from mr-quinlan
  7. shrikestrike reblogged this from mr-quinlan
  8. mr-quinlan reblogged this from fabulips
  9. love-shack-cats reblogged this from scalestails and added:
    All of these things are super important! Never kept a fish myself, but this will be a great resource if I ever decide to...
  10. neverfearlizzishere reblogged this from iantojonesthebetta
  11. kasiavandapperpants reblogged this from iantojonesthebetta
  12. iantojonesthebetta reblogged this from scalestails
  13. demjackolanterns reblogged this from scalestails
  14. akaine reblogged this from scalestails
  15. living-on-insanityy reblogged this from scalestails
  16. groinboiler reblogged this from scalestails
  17. gallifreyedknot reblogged this from rallieroarz
  18. rallieroarz reblogged this from scalestails
  19. yeahdragon reblogged this from reyairia
  20. sailor-2007-or10 reblogged this from scalestails