Fish Species Explained – Goldfish
Scientific Name: Carassius auratus
Lifespan: 10–15 years on average (up to 20+ with excellent care)
Size: 6–8 inches (common); fancy varieties stay smaller
Origin: East Asia; domesticated from wild carp over 1,000 years ago in China
Temperament: Peaceful, social
Best Kept: In a tank or pond (not bowls)
All you need to know in our Fish Species Explained – Goldfish
Tank Size and proper Filtration are essential when raising goldfish. Minimum tank size is 20 gallons for one goldfish. Add 10–20 gallons per additional goldfish. Fancy varieties (e.g., orandas, ryukins) need slightly less room than common or comet goldfish. High filtration is a must; goldfish are messy. Use a filter rated for 2–3× your tank volume. Test water weekly, use a gravel vacuum to clean the substrate. Avoid overfeeding — only what they eat in 2 minutes. Always Quarantine new fish for 2–4 weeks
Proper water conditions for your gold fish to thrive is a temperature around 65–75°F (fancy varieties prefer 68–74°F). Keeping pH levels between 7.0–8.4. Ammonia & Nitrite: 0 ppm. Nitrate: < 40 ppm. Perform 25–50% water changes weekly
Goldfish are Omnivores and should be fed a varied diet. Good base of high-quality goldfish pellets, supplement with Blanched veggies (peas, spinach, zucchini), Bloodworms, brine shrimp (occasional treat). Avoid too much protein, low-fiber food (causes bloating/swim bladder issues).
Common Goldfish Varieties:
- Common Goldfish: streamlined body, great for ponds
- Comet: similar to common but with a longer tail
- Shubunkin: calico coloration, pond-friendly
Fancy Goldfish Varieties:
- Fantail: double tail, rounder body
- Oranda: fleshy head growth (“wen”)
- Ryukin: hump-backed, deep body
- Ranchu: no dorsal fin, highly rounded
- Bubble Eye: sacs under eyes — very delicate
Common health issues when thinking about Fish Species Explained – Goldfish are Swim Bladder Disease, which is floating/sinking issues; often from overfeeding. Ich (White Spot Disease), this is when tiny white spots develop on the fish. Requiring treatment with a combination of heat and medications. Fin Rot can also be an issue for goldfish causing fraying fins from poor water or an infection. Lastly, Goldfish can experience constipation. This should be treated with peas or fasting.
Behavior and compatibility for goldfish is social as they prefer being in groups of at least 2 to 3, if the tank or pond allows. Avoid aggressive or fast-swimming tank mates as this will cause stress for the fish. Fancy goldfish should not be housed with common or comet goldfish as they’re slower and will be outcompeted for food.
A common misconception about gold fish is that they have 3-second memories, this is false. They can learn routines and recognize people. Check our other article where scientist taught goldfish to drive. You’ll find that goldfish are easy to keep providing you are well informed.
Don’t forget to check out our Facebook Page for latest aquarium blogs, coupons & news! From an Aquarium Plants to Maintenance Care and Fish Tank Aeration to Rocks & Woods, we have you covered! If you have any questions call us at 856-985-9339 or email us at sales@aquariumh2o.com.








