Freshwater Aquarium Equipment

By Jason Troxel

We think of 'aquariums' as the glass boxes that hold our fish, corals, plant life, and decorations.  But, whether it's freshwater or saltwater, there is a lot more going on behind the wizard's curtain.  Today we're going through the absolute beginner's list of equipment needed to start a freshwater aquarium.  I'll provide a separate saltwater list in my next post, and you will see that there is overlap between the two formats.

Must Haves:

Heaters / chillers - your fish and other inhabitants primarily come from nature - although captive bred is becoming more prevalent in our hobby, the truth is that over 90% of all tank inhabitants are pulled directly from their native habitats.  To become happy and healthy inhabitants of their new home, the hobbyist needs to understand what temperature they require.  Freshwater fish fall into four main temperature bands: Warm Tropical, Tropical,  coldwater, and temperate.   Coldwater fish will present a challenge to the freshwater hobbyist because of the need to cool the water with a chiller.  

Regardless of which temperature band you're in, the most important key to success is stability.  Heaters are the number one cause of tank failure .  These units turn on and off hundreds of times per day, every day, for as long as they're in service.  For this reason, VTC recommends having two heaters installed on a temperature probe that controls their heat transfer.  I also recommend alarms be put on the tank for high temp alerts; you will likely not notice a failed heater until it's too late and your fish are stew or fishcicles.  By having an alarm, you'll have an opportunity to catch the temperature trend before it becomes fatal.  Finally, I also recommend replacing heaters every year to two years; heaters are relatively cheap and this is just good insurance against undesired failure.  

Thermometers - we just spoke about the importance of keeping temperatures stable; a thermometer is used to validate your water temperature and can also be used to provide the alarming functions.  Where I've recommended that heaters be replaced periodically, I choose a very high quality thermometer because their lifespan is very good.  I.e., spend a little more money here to get what will serve you for years.

Filters - Filters serve two purposes, to remove detritis from the water column and to host nitrifying bacteria that convert ammonia in the first step of the nitrogen cycle.  Filters are rated for tank size and the amount of water you want to change every hour.  The most popular style of filter for freshwater tanks is the canister filter; the next most popular is the hang off the back (HOB) filter units.  Both of these systems use a pump to withdraw water from the main display tank, into the filter unit, through several different pads or media, and then back out of the filter, returning to the tank.  The general rule of thumb is that a freshwater filter should turn over the water in the tank at least four times per hour. This means that if you have a 50-gallon tank, your filter should have a flow rate of at least 200 gallons per hour.

Light - Lighting on a freshwater tank can be as simple as something to illuminate the interior of the tank so that you can see in and enjoy it, or more complex to provide photosynthetic light for plant life.  In both of these use cases, the light on a freshwater tank is surprisingly uncomplicated and affordable.  The same is not true for saltwater reef tanks.  We'll talk about that in the saltwater section.

Substrate -  Substrate is a fancy word to describe the material that lines the bottom of your aquarium.  The two most common substrates in freshwater tanks are gravel or sand, both of which support the growth of beneficial bacteria.  For those with live plant tanks, soil is also very common; soil provides nutrients for the plants, and it helps to keep the water quality in the tank stable. However, soil can be more difficult to clean than gravel or sand. 

Water conditioner - as mentioned in the post Water by Any Other Name the water used in freshwater aquariums is most likely coming directly from your tap and into your tank.  The water from your tap, however, is deadly to your fish unless it has been conditioned to remove the chlorine used to keep it safe for human consumption.  Thankfully, this is a very easy process for freshwater tanks by way of a concentrated water conditioner.  There are a variety of products available, and most can be obtained for under $20 a bottle, which will last (typically) about six months of for the average hobbyist.

Water Test Kits -  this is an extremely important piece of equipment for a new tank, because this will be the method you use to determine when it's safe to put fish (or additional fish) into your tank.  When I set up a freshwater tank, I tend to do daily water tests for the first two weeks, followed by a water test every three days, following by a water test once a week. So, the total testing of my water is usually about 2 to 3 months up front.  I will also use the test kit if I add more than one or two fish at a time - especially for smaller tanks.  However, once the tank biome is established, you can put your test kit away.  My freshwater 75 gallon tank has not been tested in at least five years, and I've hosted at least 8 pregnant Mollies who've given birth to dozens of fry at a time (the  most recent was earlier this week!).   Test kits are absolutely necessary equipment, but they have a short lifespan of usefulness to the hobbyist.

Water Pump - if your filtration method does not include a pump, you'll need one to move water in the tank.  Fish do not do well in stagnant water.  

Glass/acrylic appropriate scraper - A healthy tank has algae.  It will collect on everything, from your artificial decorations to the glass of your aquarium.  In order to clean the walls of your aquarium, you'll want a scraper that is appropriate for the material of your tank.  This is another area that I spend a little more money up front; I tend to get the scrapers that allow you to replace the scraper blades.  I do not use magnetic scrapers on my freshwater tanks, but that's primarily because they're small enough that I can do it all by hand.  

Optional Equipment:

Siphon  -  A siphon is used to remove water from your aquarium for cleaning and water changes.  This is highly recommended, but the hobbyists can get by with buckets for water removal and replacement.  In some cases the hobbyist might need to use buckets because of the distance from a water tap, too.  I have both 50' and 100' hoses in my house and I find that they are very convenient; however, I also own any number of 5-gallon buckets (mostly leftover from salt purchases) and have started using these on my freshwater tank because of its location in reference to a water source.  You can get by with either method.

Air stone / air pump -  An air stone is not necessary for a freshwater tank, but it can be beneficial for a number of reasons. Air stones add oxygen to the water, which is important for the health of your fish. They also help to circulate the water, which can help to prevent the build-up of waste products. Additionally, air stones can help to create a more natural environment for your fish.  If you decide to use an air stone, there are a few things to consider. First, you will need to choose the right size air stone for your tank, and the right size air pump for your stone. Second, you will need to place the air stone in a location where it will not disturb your fish. Third, you will need to clean the air stone regularly to prevent the build-up of algae. 

Fish Net - Personally, I think of a fish net as essential equipment, but honestly it's not until you want to remove a living fish.  I use my fish net to remove dead fish (though I've also done this by hand) and to skim the top of the tank for any detritus floating around after I clean the glass.   

Timer Power Controller  - just like the ones popular with Christmas lights, you might want the convenience of having your lights turn on and off each day at the same time without your intervention.  These controllers are cheap, reliable, and do exactly as advertised: automate your lights.  

CO2 System - If your intent is to have a freshwater aquarium with lots of living plants, you'll probably find yourself looking into CO2 Systems.  Be warned: these are not for the novice hobbyist.  You'll need a CO2 cylinder, a regulator, a diffuser, a bubble counter,  a check valve, a solenoid valve, and a CO2 reactor.  These components are most often sold separately with you needing to assemble and tune the device in order to get the desired results.  For this reason I tend to recommend this be added after the hobbyist is comfortable with the tank biome.