Sponge Filter or Hang-on-Back for a Betta?
Sponge for most betta tanks, hang-on-back if you baffle it. What each one actually does, what it costs, and how they fail.
A field guide for betta keepers · August 2026
Bettas are bred well
and kept badly.
We recommend the minimum conditions that keep a betta healthy, not the minimum that keeps it alive. Everything here runs on 4 tanks in Riverview, Florida, and is checked against veterinary and welfare sources.
Read the guidesIdentify a sick betta
Illustrative composite. Male bettas must not be housed together.
Latest guide
Browse every guideRecently published
Halfmoon or Crowntail: Which Betta Tail to Choose
Both are beautiful and neither swims well. What each tail costs the fish, which is easier to keep, and what to look for in the shop.
Betta Water Temperature: The Range and Why Stability Wins
Hold 25 to 28 degrees Celsius. Why a steady imperfect temperature beats a perfect one that swings, and how to actually keep it there.
Your Betta First 48 Hours at Home: What to Do
The two days that decide whether a new betta settles. Acclimate, then leave it alone. What to skip, and what actually needs doing.
Betta care basicsComplete guide
Betta Fish Care: The Complete Guide for Beginners
Everything a new betta keeper needs: tank size, heating, cycling, feeding and the myths that kill fish. Written from four tanks, not from a care sheet.
How to Test Betta Tank Water: A Practical Walkthrough
Which kit to buy, how to run each test without misreading it, how often, and what to do with the numbers once you have them.
Can Bettas Live in Tap Water? Tap, RO and Well Water Compared
Treated tap water suits most bettas. Why RO and distilled water on their own do not, and what well water needs before it goes in a tank.
Browse by topic
- Betta care basicsI have one. Now what?Everything a new betta keeper needs in the first month, and the myths that cause most of the damage. If you were sold a bowl and a fish in a cup, start here.
- Tank setup and equipmentWhat do I actually need to buy?Tanks, heaters, filters, lights and plants, tested on real setups. We never recommend a tank under five gallons, and we say when we have not personally run a product.
- Water quality and maintenanceIs my water actually safe?The nitrogen cycle, water parameters and testing, explained without hand-waving. Most betta deaths are water quality problems wearing another name.
- Feeding and nutritionWhat and how much do I feed?Bettas are carnivores, and most are overfed. We give portions as a countable number of pellets rather than a vague pinch.
- Health and diseasesSomething is wrong. What is it?Symptom-first identification and treatment, sourced to veterinary and welfare literature. We give honest prognoses, including when a condition is usually fatal.
- Types, behaviour and breedingWhat kind is mine, and what is it doing?Tail types, colours, and what betta behaviour actually means. Plus tank mates that work, and the ones sold to you that do not.
Start here, in this order
New keeper? Do these one at a time, not all at once.- Get the tank rightFive gallons minimum, and never a bowl. Everything after this is easier if you get it right first.
- Heat it and filter itBoth, always. Neither is optional for a tropical fish, whatever the kit box says.
- Cycle it before the fishThree to six weeks with the tank empty. This is the step nobody at the shop mentions.
- Learn the numbersAmmonia and nitrite must read zero. Almost everything that looks like illness starts here.
- Feed far less than you thinkTwo to four pellets, once or twice a day. It looks like nothing, and it is correct.
Already have the fish and no cycled tank? Most people arrive here that way. It is recoverable, and it is not your fault. How to cycle a tank with the fish already in it.
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