The core fish tank stuff you need comes down to six things: a tank, a filter, a heater (for tropical fish), a light, a substrate, and a water conditioner. Everything beyond that is either optional or species-specific. If you're new to the hobby, the list of available products can feel overwhelming, but the fundamentals haven't changed in decades.
This guide breaks down each category of fish tank equipment and supplies, explains what actually matters, and points you toward specific products worth buying. I'll cover everything from the basics to the gear that makes ongoing maintenance easier.
The Tank Itself: Size and Shape
The single most common mistake new fish keepers make is buying too small a tank. A 1-gallon "starter kit" looks affordable at the checkout, but small tanks crash fast. Ammonia spikes in a 1-gallon tank within 24 hours without water changes. Temperature fluctuates wildly with room conditions. There's no room for error.
A 10-gallon tank is a far better starting point. It's cheap, widely available, and stable enough for a beginner to cycle and maintain without constant intervention. The Aqueon 10 Standard Aquarium (bare tank) runs about $15-20 when not on sale, and starter kits like the Aqueon 10 LED Aquarium Kit include a filter, light, and heater for around $50-65.
If you want a display tank for a living room or desk, consider longer, shallower tanks over taller ones. Fish swim horizontally, not vertically. A 20-gallon long tank gives fish more swimming room than a 20-gallon high, even at the same water volume.
Filtration: The Backbone of a Healthy Tank
Filtration does three jobs: mechanical (trapping debris), biological (converting ammonia to nitrite to nitrate via bacteria), and chemical (removing discoloration and certain compounds). Most fish tanks need all three working together.
Hang-On-Back Filters
Hang-on-back (HOB) filters are the most common choice for beginner and intermediate setups. The Aquaclear 20 handles tanks up to 20 gallons and is adjustable, which matters if you keep bettas or other fish sensitive to current. Media is replaceable independently, so you don't have to throw away your beneficial bacteria colony every time you swap a cartridge.
The Fluval C Series HOB filters cost more but offer five-stage filtration in a single unit, which can simplify maintenance on larger community tanks.
Canister Filters
For tanks 40 gallons and above, canister filters offer superior biological capacity. The Fluval 207 handles tanks up to 45 gallons and runs very quietly. The Eheim Classic 250 is a simpler design that aquarists have relied on for over 30 years without issues.
Sponge Filters
Sponge filters are cheap, nearly indestructible, and safe for fry, shrimp, and bettas because there's no intake that can trap small animals. The Hikari Bacto-Surge Foam Filter paired with a Tetra Whisper Air Pump handles breeding tanks and small setups reliably.
Heating for Tropical Fish
Most popular aquarium fish, including tetras, guppies, cichlids, gouramis, and bettas, are tropical fish that need water between 72°F and 82°F. An aquarium heater is not optional for these species.
Submersible heaters work better than old-style hang-on heaters that only partially submerge. The Aqueon Pro 100W Adjustable Heater is reliable up to 30 gallons and holds temperature within 1°F of the set point. It shuts off automatically if it overheats or runs dry, which prevents the glass cracking disaster that cheap heaters cause.
For larger tanks, go with two smaller heaters instead of one large one. Two 150W heaters in a 75-gallon tank provide backup if one fails, which is worth doing if you're keeping expensive fish.
Always use a separate thermometer. The Marina Floating Thermometer is accurate and easy to read. Stick-on strip thermometers are fine for a quick check but consistently read 2-3°F below actual water temperature.
Lighting: Function and Spectacle
Light serves two purposes in a fish tank: illuminating the fish so you can actually see them, and supporting plant growth if you keep live plants.
Basic LED Fixtures
Most beginner tank kits include a basic LED bar that handles both functions for low-light plants. The Nicrew ClassicLED Plus is an aftermarket option that provides a noticeable color improvement over generic kit lights at around $20-35 depending on size. It makes fish colors pop without the expense of a full planted-tank lighting rig.
Planted Tank Lighting
If you intend to grow live plants beyond anubias and java fern, you'll need higher-intensity lighting with a spectrum that supports plant growth (peaks around 6500K color temperature). The Fluval Plant 3.0 LED is the standard recommendation for planted tanks up to 48 inches. It's programmable and mimics sunrise and sunset cycles, which reduces fish stress.
What to Put in the Water
Water straight from the tap contains chlorine and chloramine. Both kill beneficial bacteria and stress fish. You need to treat tap water before it goes in the tank.
Seachem Prime is the most efficient water conditioner on the market. One capful treats 50 gallons and it neutralizes chlorine, chloramine, and temporarily binds ammonia, which gives a new tank more time to cycle. A 250mL bottle runs about $10 and treats 2,500 gallons, making it significantly more economical than API Stress Coat or Tetra AquaSafe.
For testing your water, the API Freshwater Master Test Kit is the standard recommendation. It covers ammonia, nitrite, nitrate, and pH. Test strips are faster but unreliable enough that they've misled countless fish keepers into thinking their tank was safe when it wasn't.
For a broader look at what fish tank supplies are worth buying, the guide to the best online fish supply store covers where to find equipment at good prices. If you're specifically researching aeration, the oxygen machine for fish tank price guide compares air pump options and what they actually cost.
Substrate and Decorations
Gravel or sand goes on the bottom of the tank. Fine gravel at 1-2mm grain size is versatile: it looks natural, is easy to vacuum, and works for most fish. Coarse gravel (3-5mm) traps waste between pieces and is harder to clean. Sand looks cleaner but requires an undergravel filter or occasional stirring to prevent anaerobic pockets.
For freshwater planted tanks, Fluval Stratum is the standard planted substrate. It's volcanic in origin, slightly acidic, and packed with nutrients for plant roots. It's not ideal for fish that dig constantly, like some cichlids, since it breaks down faster when disturbed repeatedly.
Decorations are personal preference with one rule: no sharp edges. Run pantyhose across any decoration before putting it in the tank. Snags mean fin damage.
Food and Feeding Equipment
Overfeeding is the single biggest cause of poor water quality in home aquariums. Fish need less food than you think: a small pinch once or twice a day for most species, with a fasted day once a week to clear their digestive systems.
Quality flake foods include TetraMin Tropical Flakes and Omega One Freshwater Flakes. For bottom feeders like corydoras and plecos, sinking wafers like Hikari Sinking Wafers get food where it needs to go without it dissolving on the surface first.
An automatic fish feeder like the Eheim Auto Feeder handles vacations without a fish-sitter. It dispenses a precise, set amount of food at scheduled times and runs on AA batteries for months.
FAQ
What fish tank stuff do I absolutely need to get started? The minimum list is a tank (10 gallons or larger), a filter, a heater if you're keeping tropical fish, a light, a substrate, a thermometer, and water conditioner. Everything else builds on those basics. Don't buy a tank without a filter, and don't add fish to an uncycled tank.
How long does it take to cycle a new fish tank? A fishless cycle using ammonia takes 4-6 weeks. Using live bacteria supplements like Tetra SafeStart Plus or API Quick Start can shorten that to 1-2 weeks. Adding a used filter sponge from an established tank can cycle a new tank in days. Without cycling, ammonia kills new fish within a week.
Is gravel or sand better for a fish tank? It depends on the fish. Corydoras and other bottom-feeding fish prefer sand because they sift through it for food and don't damage their barbels. Cichlids that dig favor coarse gravel or even bare-bottom tanks. Most community fish do fine in either. Fine gravel at 1-2mm is a good all-around choice if you're unsure.
How often should I clean my fish tank? A 25% water change weekly is the standard recommendation for most community tanks. Gravel vacuuming during water changes removes waste buildup. Filter media should be rinsed in old tank water (not tap water, which kills beneficial bacteria) every 3-4 weeks. Deep cleaning the entire tank, including scrubbing every surface, is almost never necessary and disrupts your nitrogen cycle.