Betta (Siamese fighting fish)
Species Freshwater fish Betta splendens
Written with AI assistance, not yet checked by a person. Treat the details as a starting point and confirm important decisions with a vet or a breeder.
Overview
A colourful labyrinth fish of about 6-7 cm that breathes air at the surface. Males must be kept one per tank because they fight each other. It needs a heated, filtered tank of at least 25 L (bigger is easier), warm water around 24-28 °C, gentle flow and a lid. Lives about 3-5 years.
Wild bettas live in shallow, plant-rich still waters such as rice paddies and ditches in Thailand and neighbouring countries. They were bred for fighting and later for colour and fins; today there are many fin forms (veiltail, halfmoon, crowntail, short-finned plakat). The idea that a betta can live in a small bowl is a myth.
- Purchase price
- Pet quality €5–30
- Care difficulty
- Beginner
- Colours and markings
- Red, blue, turquoise, black, white, yellow, copper and many multicolour patterns; wild-type fish are duller.
- Long, flowing fins
- Yes
- Adult body length
- 5.5–7 cm
- Good with other pets
- Activity pattern
- Diurnal
- Temperament
- Curious and responsive to its keeper. Males flare at their reflection and at other males and will fight to injury; some also attack colourful, long-finned tankmates. Females are less aggressive but still territorial. Breeding: the male builds a bubble nest, guards eggs and fry, and the female must be removed after spawning.
- Temperament
- Semi aggressive
- Schooling fish
- No
- Nips the fins of other fish
- No
- Keep only one per tank
- Yes
Health and common problems
These are common issues for this animal, not a diagnosis. If you are worried about your animal, see a vet.
Columnaris (cotton-wool disease)
Frequency: Uncommon Serious
A bacterial infection that causes white or grey patches on the mouth, skin and gills. It spreads fast in warm water with poor quality and is often confused with fungus.
- Signs to look for
- Fluffy or greyish patches, a white rim around the mouth, a pale band on the back (saddleback), frayed fins, fast breathing.
- When to see a vet
- Quickly, because it can kill within days; antibiotic treatment should be chosen with professional advice.
- First aid
- Do a partial water change, lower the temperature a little within the fish's range and isolate affected fish if possible.
Dropsy
Frequency: Uncommon Serious
Fluid builds up in the body, usually because the kidneys or other organs fail after a long infection or poor water. It is a sign of serious illness, not a disease of its own, and the outlook is often poor.
- Signs to look for
- A swollen belly and scales that stick out like a pine cone, bulging eyes, pale gills, lethargy.
- When to see a vet
- As soon as you see raised scales. Ask for advice also about humane euthanasia if the fish is suffering.
- First aid
- Move the fish to a separate tank with clean water and check the main tank's water quality for the other fish.
Ich (white spot disease)
Frequency: Uncommon Moderate
A common parasite of aquarium fish that shows as small white dots. It spreads fast in a tank and is worse after stress or cold shocks.
- Signs to look for
- White dots on skin and fins, rubbing on objects, clamped fins, fast breathing.
- How to handle it
- Treat the whole tank with an ich product made for aquariums, following the label; remove activated carbon from the filter during treatment.
- Prevention
- Quarantine new fish for 2-4 weeks and avoid sudden temperature drops.
- When to see a vet
- If fish keep dying, or you are not sure which disease it is.
- First aid
- Raise the temperature slowly within what your fish tolerate and follow the instructions of an ich treatment made for aquariums.
Velvet (Oodinium)
Frequency: Uncommon Serious
A parasite that covers the skin with a fine gold or rust-coloured dust. It attacks the gills too and can kill quickly. Bettas and gouramis are often affected.
- Signs to look for
- A golden sheen best seen with a torch, clamped fins, rubbing, fast breathing, loss of colour and appetite.
- How to handle it
- Treat early with a velvet treatment and dim the light; it can kill within days.
- When to see a vet
- If you are unsure of the diagnosis or fish keep dying. An aquatic vet or experienced fish shop can look at a skin sample.
- First aid
- Dim the tank light, check the water and use an aquarium treatment labelled for velvet, following the label.
Ammonia and nitrite poisoning
Frequency: Common Emergency
Fish waste turns into ammonia and nitrite, which are toxic. In a new tank that is not cycled yet, an overstocked tank, or after the filter bacteria are destroyed, levels rise fast. This is the most common cause of death of new aquarium fish.
- Signs to look for
- Gasping at the surface, red or dark gills, lethargy, clamped fins, sudden deaths, cloudy water.
- Prevention
- Cycle the tank for 4-6 weeks before adding fish, add fish gradually, do not overfeed and test the water weekly.
- When to see a vet
- If fish keep dying after the water tests are normal again. Prevention is cycling the tank for several weeks before adding fish.
- First aid
- Test the water at once, do a large water change (with conditioned water at the same temperature), stop feeding for a day and do not clean the filter in tap water.
Fin rot
Frequency: Common Mild
Bacteria eat the edges of the fins, usually after poor water quality, injury or stress.
- Signs to look for
- Ragged, shortened or whitish fin edges, red edges at the base.
- How to handle it
- Correct the water first; most mild cases heal. Use medication only if it spreads.
- Prevention
- Keep the water clean with weekly partial changes and avoid fin-nipping tankmates.
- When to see a vet
- If the rot reaches the body or does not improve after the water is corrected.
- First aid
- Test the water and do a partial water change. Keep the tank clean.
Swim bladder disorder
Frequency: Common Moderate
The fish cannot control its buoyancy. It is a symptom rather than one disease: overfeeding and constipation, poor water, infection or body shape (short, round-bodied fancy fish) can all cause it.
- Signs to look for
- Floating at the surface, sinking to the bottom, swimming on the side or head-down, a swollen belly.
- Prevention
- Feed a few pellets once or twice a day and leave one day a week without food.
- When to see a vet
- If it lasts more than a few days, the scales stick out, or several fish are affected.
- First aid
- Test the water, do a partial water change, and stop feeding for a day or two, then feed small amounts.
Care and maintenance
-
25 % water change
every week
Siphon about 25 % of the water from the bottom and refill with conditioned tap water at the same temperature.
-
Test the water
every week
Check ammonia, nitrite and nitrate (and pH); act on any ammonia or nitrite reading.
-
Rinse the filter sponge
every month
Squeeze the sponge in a bucket of old tank water, never under the tap: tap water kills the useful bacteria. Replace media only in parts.
-
Count the fish and check the temperature
every day
At feeding time count the fish, look for clamped fins, spots or heavy breathing, and read the thermometer. Remove uneaten food after a few minutes.
-
Clean the glass and trim plants
every 2 weeks
Wipe algae from the front glass and remove dead leaves.
Sign in to add these tasks to your reminders for your Betta (Siamese fighting fish).
What it costs
This is an estimate, not a quote. It multiplies typical amounts by typical prices in Serbia. Your real costs depend on the shops, the vet and the animal. Change the assumptions below to match your situation.
Who it gets along with
Worked out from the traits of this animal. Individual animals differ, and introductions should always be slow and supervised.
Be careful with
-
Cats
Based on the typical temperament of Betta (Siamese fighting fish) (2/5). -
Dogs
Based on the typical temperament of Betta (Siamese fighting fish) (2/5). -
Small pets
Based on the typical temperament of Betta (Siamese fighting fish) (2/5). -
Birds
Based on the typical temperament of Betta (Siamese fighting fish) (2/5). -
Fish
Based on the typical temperament of Betta (Siamese fighting fish) (2/5).
Not enough information about: children, seniors, strangers.
Notable cases
- Betta (Siamese fighting fish) (Avoid with): Two males fight to injury or death. Do not keep two bettas in one tank, even with a divider unless you are experienced.
- Neon tetra (Be careful with): Contested: in a planted tank of 60 L or more many bettas ignore a group of neons, but some hunt them, and neons prefer slightly cooler water. Watch closely and have a plan B.
- Guppy (Avoid with): Avoid: male guppies have colourful, flowing fins that bettas often mistake for a rival and attack; guppies also nip at long betta fins.
Set-up and food
- Minimum group size
- 1 animals
- Water temperature
- 24–28 °C
- pH
- 6–7.5
- General hardness (GH)
- 3–15 dGH
- Minimum tank size
- One animal 25 l
- Swimming level
- Top
- Needs live plants
- No
- Needs hiding places
- Yes
- Water flow
- Low
- Jumps, needs a tight lid
- Yes
- Diet type
- Insectivore
Betta 60 L planted
60 L About €180 (estimate)
A 60 L tank with a gentle sponge filter, 50 W heater, lid, LED light, fine gravel or sand, many live plants (also floating plants) and a few caves. Room for one male betta and later a small group of peaceful bottom fish.
- Aquarium tank – 60 L
- Aquarium filter – sponge filter
- Aquarium heater – 50 W
- Aquarium thermometer
- Aquarium lid
- Aquarium light
- 10 × Live plants
- Water conditioner
- Water test kit
Betta 30 L nano
30 L About €110 (estimate)
The smallest sensible set-up for one betta: 30 L, gentle filter, 25 W heater, lid and plants. Needs the same weekly water changes as a big tank.
- Aquarium tank – 30 L
- Aquarium filter
- Aquarium heater – 25 W
- Aquarium thermometer
- Aquarium lid
- 5 × Live plants
- Water conditioner
Equipment
Required
-
Aquarium filter
Keeps the water clean and moving and holds the useful bacteria; sized to the tank. A sponge or adjustable filter with gentle flow; cycle the tank for 4-6 weeks before adding the fish. -
Aquarium heater
Holds the water at the right temperature; a thermostat model is the norm. -
Aquarium lid
Stops fish that jump and slows evaporation. Bettas jump; leave a few cm of air under the lid because they breathe at the surface. -
Aquarium tank
at least 25 L
Glass or acrylic tank on a stand that carries the full weight (about 1 kg per litre). -
Aquarium thermometer
Checks that the heater works; read it daily. -
Water conditioner
Removes chlorine and chloramine so tap water is safe for fish. -
Water test kit
Drop tests or strips for ammonia, nitrite, nitrate, pH and hardness. Ammonia, nitrite and nitrate; daily during cycling, weekly afterwards.
Recommended
-
Aquarium light
LED lighting on a timer, about 8 hours a day; stronger light is needed for demanding plants. -
Gravel siphon and bucket
For water changes and cleaning the substrate; keep the bucket only for the aquarium. -
Live plants
Use up waste, give cover and calm shy fish; easy species need no extra fertiliser.
Food
- Micro pellets / granules – 2-4 small pellets per meal. Once or twice a day; one fasting day a week.
- Frozen bloodworms – 1-2 times a week as a treat, thawed.
- Frozen brine shrimp or daphnia – 1-2 times a week.
- Flake food – Accepted, but pellets are easier to portion.
Breeding
- Breeding type
- Bubblenest
Breeding is a big responsibility. Many animals in shelters are waiting for a home; ask a vet and a breeders association before you plan a litter.
Legal
Check your local law. Rules about keeping, importing and selling animals differ between countries and regions and change often. What is written here may be out of date; ask your local authority before you buy or adopt.
No specific legal rules are recorded for this animal.
General information, not veterinary advice. Every animal is an individual. Typical values and costs are estimates. Talk to a vet, a breeder or a shelter before you decide, and see a vet if your animal is unwell.