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How to Make a Freshwater Tank Look Like a Saltwater Tank

Saltwater aquariums are so wonderful to watch. It would be so nice to have one but what if you already have a freshwater tank and don’t really want to set up a new one? Can you somehow make your current freshwater tank look like a saltwater tank? Well, sure you can! It will take a bit of work but when your project is complete, it will be so satisfying.

A freshwater tank can look like a saltwater tank by changing out gravel for sand, taking out live and fake plants and replacing it with fake live rock and fake coral. The fish displayed in the freshwater tank should have bright coloring if you want them to look like saltwater fish.

Above are just a few examples of what you could do. I will go over those more in detail below as well as add a few more ideas so the next time someone is looking at your tank, they might just ask you when you set up a saltwater aquarium?

Changing Substrate to make a Freshwater Tank Look Like Saltwater

Out of all the ideas in this article, I feel this is the one that will make the most difference. Getting rid of your coloured aquarium gravel and replacing it with sand will be the biggest change in appearance and is also the most important one to make sure you do right.

Firstly, yes, I recommend changing any and all substrates to a sand substrate, if you want to have your tank looking more like a saltwater aquarium. There is more than one option of sand you can use.

There are aquarium sands that your local fish store or online stores like Amazon stock. There is the option of using pool filter sand, which is very cheap. However, you do not get the colour options like buying aquarium sand from the fish store.

Another option is play sand, which I do not recommend. I know some hobbyists use it, but I just find that if you have a strong water flow in the tank, it moves around a bit too much for my liking.

The idea of this article is to make your tank look like a saltwater tank, so if you can get yourself some white sand, you’re 60% of the way there.

If you are changing out an existing tank’s gravel for sand, you cannot just scoop out the gravel and drop the sand in. The gravel has most of the tank’s beneficial bacteria living and growing in it. You need to do this in sections over time. If you do not do this fractionally, you run the risk of killing some (or all) of your fish. Here is what I recommend you do.

  • Pick ¼ of the tank floor and scoop out the gravel in that section. Use something to stop the remaining gravel from moving into that section.
  • Wet the aquarium sand you are placing into the tank for this ¼ section.
  • Taking a large ladle or something similar, slowly lower sand into the section of the tank that you just removed the gravel from.
  • Continue on until that area is now sand.

There will be sediment and sand clouding up the tank for a while, but it will settle in a short period of time.

I would wait about a week before you do the next section. Changing out the gravel for sand this way should take you about a month (4 weeks). It will be worth it when finished as all your fish should survive the changeover.

By the time the month is up, the sand will have a lot of new beneficial bacteria growing in it.

*Check out this aquarium sand on Amazon*

Caution: Do not put crushed coral made for marine tanks in your freshwater aquarium. This substrate is made specifically for a marine tank and will affect the water parameters. It will raise PH and could be harmful to your fish. Make sure whatever you purchase is freshwater-safe.

Updating Your Aquarium Lighting to Look Like a Saltwater Tank

Believe it or not, your fish tank lights could make your water look like saltwater than freshwater – if you get the right set-up.

There are 2 things I would look for to accomplish this. Very bright white lights and the shimmer effect. Let us look at both.

  • Bright white lighting will show off all the colors your fish display. Also, after putting in the white sand, your tank substrate will reflect the light just like shallow ocean water does around reefs and beaches.
  • Have you ever watched a show on TV with underwater divers filming? When they film near reefs, the water shimmers from the movement of the water and the light shining down into it. Well, surprise-surprise, you can purchase bright aquarium lighting that comes with the shimmer effect!

*If you want to check one of these shimmering lights here is one on Amazon*

Updating Your Fish Tanks Decorations to Make it Look Like a Saltwater Tank

The easiest way to make your freshwater tank look like a saltwater tank is to take out all the fake plants and decorations. Start with a clean slate.

Go have a look at fake live rock or dead (live) rock at your local fish store. Also, check out large cichlid tanks and consider having decorations similar to those. Do not put too many in the tank though. You want the rocks to be there but be subtle.

You can also purchase things like fake corals made of plastic and cements. Consider putting some of these in the tank to give that saltwater vibe.

Try to stick to whites and grays. If you opt for neon flashy colors, it is going to look too fake and it will ruin your tank’s chances of looking like a saltwater aquarium. That is my opinion, of course.

Switch Out Your Tanks Backdrop to Make It Look Like Saltwater

If you have a backdrop that has pictures of freshwater fish and live plants, then take it off. Invest in a simple saltwater backdrop. I would not get one that has marine fish on it as that might confuse the person watching the tank.

A nice, simple underwater ocean backdrop can really finish off the look of your tank.

Select Fish That Look Like They Come from the Ocean

If you do not already have fish in the tank, this section is for you.  Face it, if you buy a bunch of goldfish, your tank just will not have that saltwater feel.

There are lots of freshwater fish, however, that have beautiful coloring and could pass off as saltwater fish.

If you have a small tank, consider fish such as Neon or Ember Tetras. Killifish and Boseman Rainbow fish are an excellent option as well.

If your tank is close to 50-gallons or larger, consider purchasing African or South American Cichlids. German Rams are very colorful and so are Angelfish.

The beauty about this day-and-age in the aquarium hobby is we can research online if our local fish store does not have what we are looking for. You can even have freshwater fish shipped to you from a breeder/supplier.

The more colorful your freshwater fish, are the more your new tank set-up will appear to be a saltwater aquarium.

Water flow So Your Freshwater Tank Looks Like Saltwater Tank

One thing I notice when looking at saltwater tanks is there is usually more water flow than a freshwater set-up.

If this is something you are interested in, you could easily increase the tanks water flow just by adding a simple powerhead. If you are not sure what they are, check this one out over on Amazon.

A powerhead just moves water around. They are also beneficial to use because when positioned properly can cause more surface agitation which means more CO2 is leaving the tank and more oxygen is entering the water.

As you can see, even if you are not trying to make your tank look like a marine tank, using a powerhead is a great idea.


Just a short conclusion to point out that doing all the ideas listed above can really make a difference in how your freshwater tank appears.

Of course, there is no better way to look like a saltwater tank, unless you actually have a saltwater tank set-up. This is just a great option, if you feel like changing things up and experimenting a bit.

Thanks for reading and good luck with your aquarium!

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