Beginners Guide to Fish Keeping and Building your first Aquarium (Part 1)

4. Freshwater versus Salt Water

This is a major decision to make. Salt water has a lot more requirements for equipment and the cost of the fish are actually more than freshwater (this depending on where you live however).

Here is a list of the differences and things to consider:

  1. Freshwater setups are less complicated than Salt Water. Extra equipment and media costs due to having to purchase and mix Salt Water.
  2. Salt Water or “Marine” Fish are more expensive to own. Typically you can spend anywhere from $25.00 per fish upwards of $100.00’s of dollars per fish however typically (unless you get a really big tank), you have less salt water fish then you can freshwater so the math may or may not even out. this is all depending on what you buy and where you live.
  3. Salt Water Chemistry is different so you need salt water or Marine water testing kit and water salinity gauge. This is generally no problem however there are other factors when testing in addition to the basics (more on this later).
  4. Storage of Salt Water Mixture is recommended for easy top ups. You can’t mix up water from the tap and simply add a de-chlorinator,  You must use RO/DI  water either bought from a store or made yourself from an RO/DI  unit that you can purchase.
    View this article by one of my absolute favorite Saltwater Tank Person: Mr. Salt Water Tank  (Mark Callahan)
    Mark is great information resource for users looking to go Pro and do Salt Water correctly. But lets continue on with the basics…..
  5. Salt can be messy and will get into a lot of areas you didn’t think possible. Salt corrodes metal fast! Don’t have anything metallic near or around a salt water tank where possible !

Okay so we’ve established that if you pick Salt Water over Fresh water you have more items on the checklist to take care of and that Salt Water setups are vastly more complicated depending on what you choose.

In this article I am going focus more on Freshwater setups for new people to the hobby as an entry point.

If you want more information on Salt Water setups please visit Mr Salt Water Tank  and watch his amazing video series

What’s the Next Step ?

So we decided on what size tank we want, where were going to put it and that the floor can withstand a fully filled tank.

What Equipment are the essential Equipment that we need ?

The following Equipment are generally considered essential:

  1. Filter system with Bio-media filter
  2. Heater (for colder climates in the winter)
  3. A Fan or other cooling device like a central air conditioner / window air conditioner in the house (for Warmer climates or Summer time in your house) – Will keep temperatures in check from getting too high
  4. An overhead light with a switch to turn off and on for your tank – this can be LED, Tube or Halogen or tungsten based – the variety really varies
  5. Air Stone or Bubble wand for the tank
  6. Air Pump – to power your air stone or bubbler
  7. Tools to clean, scoop fish and test your water
  8. Essential Chemicals

To understand some of the equipment and what they do, you need to understand the chemistry of what happens in an Aquarium (and in the real world) in order to understand whats going on.

Enter the Nitrogen cycle.

Nitrogen Cycle

This is the chemical process in which Nitrogen is consumed by plants and animals and then finally broken down and the released back into the environment to start the process all over again. This process happens on land and in the water in nature.

Since you are Effectively creating an Eco system in  a box in your home you have to replicate this cycle or the chemistry and natural habitat that is present for your fish won’t work  and everything dies.

Nitrogen Cycle

This diagram taken from a google search shows how the Nitrogen Cycle Works.

1. First you put food into your tank for your fish or other species to eat.

2. That food is then consumed and waste is discarded and other  left over bits sink to the bottom as waste.

3. Fish break down  their food and expel ammonia in the water as well as the bio-matter waste. Un-eaten food also breaks down  and releases ammonia over time. (Nitrogen is a major element in Ammonia)

4. Ammonia in the water by itself starts becoming poisonous to fish at 2 parts per million (approximately). with some fish being able to tolerate more or less.

5. Bacteria in the water eat and break down the ammonia into a  more toxic form called Nitrites. Nitrites tend to be more toxic to fish.

6. A second Bacteria  (  breaks down the Nitrites into Nitrates (a lot less harmful to fish).

7. If you have live plants in your tank, they  feed on  Ammonia and Nitrates as well as the bacteria eating it.

8. If you don’t have plants, you will see a Nitrate Rise in your tank over time.

9. Weekly water changes are required to solve this problem.

Reasons why you need a filter ?

Filters with Bio-media provides several things in addition to this example of the nitrogen cycle above:

  • Filter systems  provide a lot more  filtering capacity  in tanks for their volume size then just relying on the tank to filter. Therefore more filtration = more fish and other life you can have in one tank.
  • Filter systems provide water flow and aeration  to keep water from stagnating.
  • Filters systems provide a way to filter water and remove large debris – think of a pool filter and how much yucky stuff gets removed.
  • Filter systems provide other abilities like keeping the water clear  by use of  Carbon filters.
  • Filters provide a home for the Bacteria using Bio-media. This works to provide a second source  or colony of bacteria in addition to being in the tank.  When cleaning the tank you will not totally wipe out  your bacteria colonies (not all eggs in one basket).


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