How to Have a Low Budget Fish Tank
To make your fish tank on a low budget, choose fish that don't need expensive gear or food to keep them healthy and happy so you can save money on running your tank. For example, sail-fin mollies and peppered cory catfish are great hardy fish species that cope well with basic tank environments. You might also find it easier and cheaper to have just one species of fish, but if you want several species, stick to fish that won't fight over territory so you don't have to keep replacing fish that die from stress or fighting. Avoid adding too many fish to the tank as this can stress your fish. Instead, you can save money by buying two or three pricier fish instead of lots of cheaper ones.
Buy a glass tank. Glass tanks are less expensive than acrylic tanks and they don't scratch easily. To get an idea of how big your tank should be, first determine where you'd like to put your fish tank. Large tanks require more energy to heat but take less effort to clean. On the other hand, smaller tanks need fewer decorations and fish, but they'll need to be cleaned more often. Keep in mind that you'll need to set the glass tank on a level surface that can support a lot of weight. Choose a filter. You can choose a mechanical, chemical or biological filter for your tank. Keep in mind that many filters perform a combination of these types of filtration, but you must have biological filtration to keep the tank clean. Ensure that you choose a filter that works for the size of tank you've chosen. You can choose from a canister, power filters (that hang over the side of the tank), or wet/dry filters. Canister filters are usually the most cost-efficient choice. Remember that you'll need to clean the filter regularly so that it works properly. Purchase a heater. Most fish that you'll put in your freshwater aquarium will need the water temperature to be between 75 and 80 degrees F (24 and 27 C). The easiest way to maintain the temperature is to install a heater that automatically turns on and off as needed. Choose a heater that fits the size of your tank, keeping in mind that if you have a large tank, you'll need to get two smaller heaters. For a low-budget option, consider using a smaller tank so you'll only need to buy one heater. Purchase a mid-range priced heater since cheap heaters are more likely to fail. Pick your lighting. If you're growing your own plants in the fish tank, you'll have to use lighting. Otherwise, lights are optional and just useful for making the fish stand out. If you want to keep costs low, just use basic lighting for fish-only. This way, you'll only need one low-watt fluorescent light bulb which is inexpensive to run. For a fish-only aquarium, you'll only need 1 to 2 watts of light per gallon (3.78 liters) of water in the tank. You should buy the fluorescent light bulb from a pet store since standard bulbs can make brown algae grow. Get a hood for the tank. A hood will cover the tank so the fish don't jump out and it will keep too much water from evaporating, so you won't need to clean it as often or add water. Too keep costs down, choose a full hood. This will include the space for your fluorescent light bulb. Full hoods are typically cheaper than glass canopy hoods which require separate lighting systems. Research types of fish. Try to pick inexpensive and low-maintenance fish when you start out. Look for fish that aren't territorial since they'll be sharing the same tank. Choose fish that are easy to care for and avoid delicate fish that need water to be absolutely perfect (like neon tetras, guppies, and balloon belly mollies). Instead, consider getting: Peppered Cory catfish: Buy several of these which feed off the bottom of the tank and keep the tank clean. Black Skirt and Serpae tetras: These tetras like to live in groups of at least five. Betta: Although these fish are easy to care for, bettas are known for being aggressive if the tank is too crowded or there are more than one betta fish in the tank. Sail-fin mollies: These fish are hardy and fast swimmers. Decide how many fish you want. Although fish prices vary considerably, you should have an idea of how many fish you'd like to keep in your tank. You may be able to get lots of fish very inexpensively. Or you could choose a few fish that cost a little more. Have an idea of how much you'd like to spend before you go into the pet store so you stick to a low budget. As a general rule, you should only have one inch of fish for each gallon (3.78 liters) of water if you have a rectangular tank. You can use online calculators to determine how many fish you can put in your exact aquarium. Choose food for your fish. Research what kind of food your fish will need and find which brands carry it. You'll find that there are a number of brands that carry fish food, so the cost can vary. The brand Tetra makes a good budget fish food for every type of fish. Ask about purchasing fish food in bulk, since the pet store may have deals if you buy larger quantities. Include tank decorations. Once you've decided what fish to get, research what they need in their tank. Avoid decorating with things or colors that irritate or stress your fish. For inexpensive decorations, check out garage sales or thrift stores. Common tank decorations include: Non-toxic figurines Live rock Driftwood Choose the right gravel (substrate). For a plant-only fish tank, you can use common aquarium gravel or sand. You should fill the tank so that the gravel or sand fills about 2 1/2 inches (6.35 cm) of the tank. Sand might be the cheaper option and you can buy kids play sand (which is sterilized) or sandblasting sand. Avoid using sand from the beach since this can throw off the tank's pH balance and may still contain live organisms. Decorate with plastic plants. While you can use live plants in a fish tank, these can take up more time, effort, and money to maintain. Instead, place plastic plants in the aquarium. Plastic plants can make your fish tank look more interesting and will give your fish a place to hide and play. They don't require any maintenance. Another benefit of plastic plants is that your fish won't eat them! 
Buy a glass tank. Choose a filter. Purchase a heater. Pick your lighting. Get a hood for the tank. Research types of fish. Decide how many fish you want. Choose food for your fish. Include tank decorations. Choose the right gravel (substrate). Decorate with plastic plants. 