Fish health factors.

[PixelStormX]

Totally agree — stress is the silent killer in tanks. I'd probably add "stable routine" somewhere in there too. Sudden changes (light, temp, layout) can mess with even hardy fish.

 

[eon aquatics]

What other fish health factors are there?
Here is a list that I thought of.

Food
Light
Tannins
Water chemistry
Fish specific environment such as hiding places
Plants
Fish size related to aquarium size
Number of fish depending on the type of fish
Variety of different species
Aeration
Water current
Fish stress from water changes
Fish stress from gravel cleaning
Fish stress form cleaning away decaying plant material
Fish stress form planting new plants
Fish stress from cleaning algae
Fish stress from cleaning bacteria
Fish stress from territorial fighting
Water chemistry changes from cleaning
Temperature
Surface agitation
Compatibility of fish species
Fish activity level
Fish breeding
Fish eating aquatic plants
Fish diet
Plant root health
Chemical treatments
Stress from equipment being turned off while cleaning the equipment

 

[eon aquatics]

Combination of factors such as water changes that result in a different temperature of the aquarium water.
Cleaning a canister filter and wavemakers/air stones at the same time resulting in a difference in water agitation / current
Cleaning gravel/plants at the same time

 

[eon aquatics]

light levels that plants need
light spectrum
types of lights
over feeding
under feeding

 

[eon aquatics]

Filter GPH
Wavemaker strength
Air pump GPH
Types of filter media
Types of filters