Hi and welcome to the forum
What's a pygmy gourami, do you have a scientific name for it?
As Aiken mentioned, bigger tanks are easier to maintain. If finances are an issue, perhaps look at a 20 gallon long tank, they don't cost much more but hold a lot more water and have a much bigger surface area for any fish you get. An 8 gallon tank is an issue because aquariums don't hold the amount of water they are sold as.
(eg: an 8 gallon tank might only hold 6 gallons when it has gravel and ornaments in and is filled to a couple of inches below the top).
Perhaps look around for a tank that holds a bit more water but still falls into the budget.
What are the tank dimensions (length x width x height) that you are looking at?
Aquariums that are long and wide are better for the fish than tall narrow tanks. The surface area (length x width) allows fish to swim left and right, rather than being forced to swim up and down in a tall narrow tank. Try to avoid tall narrow tanks.
Don't buy any aquarium, filter or other related equipment until you run it past us first. A lot of shops will sell you stuff that you don't need and this will add to the overall cost and leave you with a heap of unwanted items. The main items you need are the aquarium, polystyrene foam to go under the tank if it's required, coverglass to stop evaporation and fish jumping out, gravel or sand for the bottom, a light unit if you want live plants but you don't need a light if you don't have live plants, a filter (an air operated sponge filter is sufficient for small tanks and can be cheaper than power filters, but power filters are quieter). A heater and thermometer if you go for tropical fish, and a dechlorinator to neutralise chlorine/ chloramine in tap water. A picture on the back of the tank also helps but you can use coloured card or a plastic bin liner to do the same job. A few ornaments/ plants to help the fish feel more secure. Ornaments from pet shops can be expensive and live plants are often cheaper than fake plants.
You will need a couple of new buckets and a gravel cleaner to do water changes on the tank. Try to get buckets that are food safe and use a permanent marker to write "FISH ONLY" on them. Use those buckets for the fish and nothing else.
When you do work on the aquarium, make sure you don't have any perfume, cream, oil, hand sanitiser, perfumed soap residue or anything else on your skin that can wash off into the water. These chemicals can kill everything in the tank very quickly. Wash your hands and arms with warm water before working in the tank. Use warm soapy water after you have finished working in the tank.
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What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website (Water Analysis Report) or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).
Depending on what the GH of your water is, will determine what fish you should keep.
Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.
Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.
If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.