Tank Setup
- Tank size: 55 gallons minimum for a single Jack Dempsey. 75+ for a pair or with tank mates.
- Substrate: Sand — they dig extensively
- Decor: Rocks, driftwood, and caves for territory establishment. Secure decorations well — JDs rearrange their tanks.
- Plants: They will uproot most plants. Use anubias and java fern attached to rocks/driftwood if you want live plants.
- Filtration: Heavy-duty canister filter — JDs are messy eaters and produce significant waste
Water Parameters
- Temperature: 72–86°F (22–30°C)
- pH: 6.5–8.0
- GH: 8–15 dGH
Electric Blue Jack Dempsey
The electric blue variant (EBJD) is a naturally occurring mutation that produces stunning solid electric blue coloration. EBJDs are significantly less aggressive than the standard form, making them easier community fish. However, they are also more delicate and prone to health issues. They grow slightly smaller (6–8 inches vs 8–10 for standard).
Managing Aggression
- Provide a large tank (75+ gallons) with multiple territories and visual barriers
- Only keep with other large, robust fish that can hold their own
- JDs are most aggressive during breeding — separate pairs if breeding becomes too disruptive
- A single JD in a large tank is the easiest setup for most keepers
Tank Mates
Only with other robust, similarly-sized fish:
- Other Central/South American cichlids of similar size (firemouths, salvini, severum)
- Oscars (in 125+ gallon tanks)
- Large plecos (common pleco, bristlenose in a 75+ gallon)
- Silver dollars, large barbs
Never keep with any small fish — they will be eaten.
Frequently Asked Questions
How big do Jack Dempseys get?
Standard JDs reach 8–10 inches. Electric blues reach 6–8 inches. They grow relatively slowly, reaching full size in 2–3 years.