Can I have too many plants in my aquarium?
Written by
Victoria Hayes
Reviewed by
Prof. David Walsh, Ph.D.Plants are good for the aquarium, but the tank is in danger if there are too many, two reasons: first, too many plants exhaust the oxygen at night, and at risk of suffocating the fish. Second, they cut off the circulation of water, creating dead places where poisonous gas is being thrown off. Cover not more than seventy per cent. of the surface.
Oxygen Depletion
- Plants consume oxygen during dark respiration periods
- High density causes dangerous overnight oxygen drops
- Add air stones or surface agitation at night
Dead Zone Prevention
- Maintain open channels near filter intakes/outputs
- Thin dense areas weekly to improve circulation
- Use substrate vacuums around plant bases monthly
Weekly Thinning - Maintain a fairly balanced approach. Each week, you can remove about 10-15% of plant mass. Concentrate on fast-growing stems, new surface plants, and so on. Try to leave the fore-areas clear of anything that would impede bottom-dwelling fish from sweeping through to feed. Trim the roots during each water change to prevent them from spreading and becoming a nuisance.
Take care to light your dense tanks evenly. Place your tall background plants on either side of the tank, and adjust your lights so that the beam enters at the mid-ground. Clean the glass daily where the plants come into contact with it. Turn the groups of plants in the tank over monthly.
Observe fish behavior for overcrowding indicators. Gasping for air at the surface concerns oxygen levels. Increased aggression indicates hiding spots have become dead ends. Lethargy suggests inadequate water circulation. These indications mean that thinning must occur immediately.
Your aquarium finds balance through management. Healthy plants show vibrant colors without overcrowding. Fish swim freely through open channels. Regular maintenance prevents problems before they threaten tank health.
Read the full article: Essential Aquarium Plant Care Guide
