You’re going to buy an aquarium! So you go to Walmart and you buy a aquarium kit. Now, what do you do?
The kit comes with:
- A ten-gallon (40 liter) aquarium
- A LED light
- An in-tank cartridge filter
- Some food
- A water conditioner
Ignore the directions that come with the aquarium and the directions that you can find online. They are full of profit-motivated scams. For instance, by far the biggest scam is the “replace the cartridge every month”. This is a huge money-making scam. Only lightly clean the outside of cartridges and leave them in place till they fall apart.
Now you go to the local fish store and you buy one or two 2 to 3-inch (5 to 7.5 cm) fish or five or six one-inch (2.5 cm) fish. Or maybe you buy two goldfish. You take everything home and set it up. You fill the aquarium with water, add the conditioner per the directions (this is VERY IMPORTANT if you have chlorine in your water!), and add the fish.
If you only add a few fish and you only feed in moderation (an amount equal to two eyes of each fish once a day) you will be just fine, contrary to what all the naysayers on social media say. Enjoy your tank!
A Little More Depth
Note that we like to do something called “fish-less cycling” where one doesn’t add fish immediately and one “ghost feeds” an aquarium as though there are fish in it. This “cycling” takes four to six weeks typically. We do this because it is POSSIBLE (but rather difficult) to harm fish by adding a lot of fish to a new aquarium and then overfeeding them, especially if your water has a high pH. But if you already have fish you are stuck. Just feed very lightly and you and your fish will be just fine. Probably the most common mistake beginners to the hobby make is to overfeed their fish.
When one sets up any new aquarium the water may get cloudy in a few weeks. Ignore that. It will clear in four to six weeks. Note if you do water changes to clear the water the cloudiness will just stick around longer. So don’t do water changes for the first two months or so. Your ornaments and gravel will get brown and green stuff on them. That’s quite normal and the best course of action is to learn to live with it. And that’s it. Easy!
What do I do with a New Aquarium That Already has Fish in It?
An exchange with a reader of this website is instructive here :
“Hi Dave
I need your help. I have a 20-gallon (80 liter) tank, I was advised to just add JBL Denitrol (“Instant Start Bacteria”) and add fish. I now have 9 celestial danios, 3 snails, and some shrimp, along with living plants. My nitrate and nitrite keep spiking (no ammonia). I have a sponge filter and air stone, I feed small amounts but not sure what I should do. I do NOT want to lose my fish or treat them badly. I am using Seachem Prime and adding bacteria when changing water. After reading your articles I know I have messed up but can I salvage the situation and how? PH is at 8.0. Thank you. Becci”
This was my reply:
“In reply to Rebecca … You are just fine. Probably 90% of the newbies to the hobby do exactly what you did. Here is what I would do. Do NOTHING other than feeding the danios a very small amount of food every day and leaving your light on for 8 hours a day (largely to deliberately grow algae for the shrimp to eat). Don’t do a water change, don’t clean any algae off of anything, don’t add “bacteria” (worthless), don’t vacuum, don’t clean the sponge filter, and don’t test the water. Do NOTHING for at least three months. Just let Mother Nature do her thing.
Keep the Prime to remove chlorine (It ONLY removes chlorine) from water changes you will do months down the road. If the water gets cloudy or green simply ignore it and let it go. After three months start cleaning the algae off ONLY the front and side glass. The plants will probably slowly die but they will be shrimp and snail food as they die. Enjoy a glass of wine.”
This advice will be good for ANY new aquarium with fish in it. Just do NOTHING and let Mother Nature do her thing. ONLY lightly feed the fish for at least three months.
Making Things Better for Your Fish
Now there are some easy ways to make the tank healthier for your fish:
- Only feed your fish an amount of dry food equal to the size of two eyeballs on the fish once a day (obviously if you have six fish it is the size of six fish eyeballs). Feed very lightly. The biggest mistake beginners do is to over-feed their fish. Fish are cold-blooded creatures that do not need a lot of food. Uneaten food in the aquarium produces bacteria. Bacteria produce toxins. And those toxins can kill fish.
- Ignore the directions to the filter which says to replace the cartridge every month. This is the biggest scam going on! Once every one or two months remove the brown gunk from the surface of the cartridge pad with a brush. Do not clean, replace or remove the foam pad or the media inside the cartridge (typically it is activated carbon). The brown stuff that builds up inside the cartridge is very good beneficial bacteria and is good for your fish, not bad. And the cartridge typically will last for years. Note some creative cartridge manufacturers are now bonding their cartridges with an adhesive that dissolves in one to two months and the cartridge falls apart. Replace these cartridges with 20 PPI (pores per inch) foam blocks from Aquarium Co-op or plastic pot scrubbers.
- Buy a medium-sized air pump, some air tubing, an airline check valve, and an air stone. Set it up just to bubble in the aquarium. Aeration by bubbles is one of the best ways to keep your fish healthy in the first aquarium.
- Buy some ich medication when you get your first aquarium. A new filter and a new aquarium can give some huge problems if your fish get the most common fish disease, ich (or “white spot”). Having an effective ich medication on hand is a very good idea.
- Add some colorful aquarium gravel. Get the 1/8 to 3/16-inch (3 to 5 mm) size, not the big gravel. You don’t want food dropping into the gravel where the fish can’t get to it.
- Add some decorations and some fake plants. Do not add real plants. Live plants are more difficult than fish store owners and the internet let on.
- Ignore the directions which say to buy some “instant cycling” product (“bacteria-in-a-bottle” or “ammonia detoxifying chemicals”). These are all scams. Just let the tank naturally “cycle” (“cycling” is the conversion of poisonous fish pee into non-poisonous stuff by colonies of “beneficial bacteria”). It may turn cloudy or even green in a few weeks. Ignore that. Do not do anything. No water changes, no cleaning of anything. In five or six weeks it will clear, and everything will be fine.
- If you want to speed things up you can add a sock filled with a teaspoon of black soil from the garden (commercial soils in a bag in the store are sterilized so they won’t work), soil from a potted plant, pond mud, or composted cow manure (only use compost if there are no fish in the aquarium). Just put the sock where there is a high flow of water and squeeze it every once in a while.
- When a fish is handled a lot it can die from the fish equivalent of a heart attack. When one adds fish to a new aquarium you want to avoid a fish dying unnoticed. An unnoticed fish body can decompose and rapidly kill the other fish. So a newly stocked tank should be checked every few hours for dead bodies. It’s just an unfortunate part of Mother Nature.
Further Guides:
Here are links to some beginner aquarium topics in a little more depth:
1, Because fish pee a chemical called “ammonia” and that ammonia is bad for a fish, it is desirable (BUT NOT NECESSARY) to treat a new tank for four to six weeks with a process called “cycling”:
1.1.2. A Simple Way to Cycle an Aquarium
2, All fish food found on the shelf of the local fish store is fine for all fish, with the caveat that a high protein food is better for the ecology of the aquarium:
3, Other than removing chlorine the water parameters are not important:
4, Filter is needed for all fish. But it is important to not replace or clean the filter too often:
5, The media in the filter is also important:
6, Good aeration gives healthy fish:
7, Starting a new tank one should always have a light stocking of just a few fish, with neons, discus, and a few other fish being avoided:
8, A brown film will develop on pretty much all surfaces in any new tank. Experienced hobbyists just live with it. It is part of a healthy aquarium:
1.1.9 Brown Algae in a New Tank
9, One of the most challenging tanks to keep is a tank with five or so three-inch fish and five live plants. Any beginner should start with plastic plants:
1.1.10. Plants and the New Hobbyist
10, New fish get one disease quite often. These is white specks on the skin of the fish which are called “white spots” or “ich”:
1.1.11. The Most Common Fish Disease – Ich
11, And if you want good, healthy, “happy” fish, there are five critical elements to doing that:
1.1.12. How to Make Fish Thrive
12, And the fish selection for a beginner is quite broad. This link will help:
13, Most beginners listen to the social media parroting about what is “required” for maintenance. And they end up spending way too much time for maintenance. Because they find maintenance such a pain they end up leaving the hobby. It does not have to be this way:
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