Biofilm
Surface Biofilm
A thin organic film on the water surface that interferes with appearance and sometimes gas exchange.
Quick facts
- Category
- Biofilm
- Organism group
- Biofilm
- Growth form
- Film
- Primary color
- Clear
- Secondary color
- Rainbow Sheen
- Attachment
- Weak
- Removal difficulty
- Easy
Identification
Shimmery, hazy, or oily-looking film floating on the water surface, often collecting in still corners.
- Growth form: Film
- Primary color: Clear
- Secondary color: Rainbow Sheen
Looks like: Unlike green water or surface-floating algae, this looks like a slick or protein film rather than suspended green bloom.
Where it appears
Typical affected areas
- On Glass
Common contexts
- Low Flow
- New Tank
Causes
Surface film usually appears where the surface is too still and organics can collect faster than they are processed.
Most common triggers
- Weak Surface Agitation
- Organic Loading
- Imbalanced Biological Capacity Versus Nutrient Loading
Root cause note: This is not a classic attached algae problem; it is a surface-management and organics problem.
Nutrient relevance
Balance relevance: Medium
Related nutrient issues
- Organic Excess
Film on the surface often reflects excess proteins and dissolved organics more than plant fertilization itself.
Correction hint: Increase surface agitation and reduce organic loading before chasing exotic explanations.
Treatment
Quick action: Increase surface movement and lift the film off manually with paper towel if needed.
Better agitation, cleaner water flow, and less trapped organic waste usually resolve it.
Manual removal: Lay a paper towel on the surface briefly to pick up the film without stirring it through the tank.
Difficulty: Easy
Prevention
Keep a lively surface and avoid letting organic waste accumulate in a low-flow system.
This page is designed to help with visual identification first, then causes, treatment, and prevention. Actual algae pressure can vary depending on maintenance, livestock, plant mass, light, flow, and nutrient consistency.