Table 2.
Study | Enrichment | Indicator(s) | Effect(s) |
---|---|---|---|
[82] | Gravel vs. barren | Preference (occupancy in enriched compartment) | Preference for gravel |
Sand vs. barren | Preference for sand | ||
Gravel vs. sand | Preference for gravel | ||
Submerged plant vs. barren | Preference for submerged plant | ||
Floating plant vs. barren | Preference for floating plant | ||
Floating plant vs. submerged plant | Preference for floating plant | ||
Gravel & floating plant vs. sand and submerged plant | Preference for gravel & floating plant | ||
Gravel and submerged plant vs. sand and floating plant | Preference for gravel & submerged plant | ||
Gravel image vs. barren | Preference for gravel image | ||
Sand image vs. barren | Preference for sand image | ||
Air stone vs. barren | Preference for barren | ||
[83] | Real plants (Ceratopteris thalictroides) and clay pots |
Preference (occupancy in enriched compartment) | Preference |
Behavioural diversity | No effect | ||
[84] | Sandy substrate and variety of plastic plants | Preference (occupancy in enriched compartment) | Preference; greater preference when combined with water flow |
[85] | Black tank walls vs. barren | Preference (occupancy in enriched compartments) | No preference |
Underwater image on walls vs. barren | No preference | ||
Sloped gravel vs. barren | Preference for gravel | ||
Flat gravel vs. barren | Preference for gravel | ||
Gravel vs. plastic plants | Preference for gravel | ||
Gravel & plastic plants vs. gravel or plastic plants | Preference for gravel & plastic plants over gravel or plastic plants alone | ||
Number of plastic plants | Preference for greater number of plants | ||
Visual contact with neighbouring tanks | No preference | ||
[86] | Plastic plants and PVC pipes | Preference (occupancy in enriched compartment) | Preference |
[89] | Gravel, real plants (vallis, Vallisneria spp. Including V. spiralis, V. elongata and V. tortifolia, and water trumpet, Cryptocoryne wendtii) |
Preference (occupancy in enriched compartment) | No preference |
Anxiety | ↓ | ||
Survival at 30 dpf | ↑ | ||
Body size at 60 dpf | ↓ (but no effect at 120 dpf) | ||
[81] | Shade vs. barren | Preference (occupancy in enriched compartment) | Preference for barren |
Artificial plants vs. barren | No effect | ||
Shade vs. artificial plants | No effect | ||
[90] | Cover | Preference (occupancy in enriched area) | Preference |
Artificial plants | No preference | ||
[60] | Sand and gravel, caps for refuge and natural plants (two branches of Cabombaceae and Pontederiaceae) | Cortisol (after chasing with a net) | ↓ |
[91] | Gravel, plastic ‘ruin’, three submerged plastic plants (two 10 cm tall and one 20 cm tall) | Anxiety (unstressed fish) | ↑ |
Anxiety (after exposure to unpredictable chronic stress) | ↓ | ||
Cortisol (unstressed fish) | No effect | ||
Cortisol (after exposure to unpredictable chronic stress) | ↓ | ||
Levels of reactive oxygen species (unstressed fish) | No effect | ||
Levels of reactive oxygen species (after exposure to unpredictable chronic stress) | ↓ | ||
[92] | Gravel and two 20 cm tall Acorus spp. plastic imitations | Activity | ↓ |
Cortisol | ↑ (but not as high as in fish exposed to a stressor) | ||
Proliferating cell nuclear antigen-expressing cells in the telencephalon | ↑ | ||
[94] | Floating plastic plant | Aggression-induced morbidity and mortality | ↓ |
Cortisol | ↑ (after 5 days); ↓ (after 10 days) | ||
[95] | Sand, plants, artificial rock formation | Anxiety | ↓ |
Exploratory behaviour | ↑ | ||
Inhibitory avoidance | ↓ | ||
Telencephalic expression of genes related to stress response | ↓ | ||
[47] | One artificial plant | Anxiety | ↓ (when combined with presence of other fish) |
[96] | Two plastic plants, one plastic shelter, gravel substrate and a novel object (white PVC pipe, rock, different coloured plants or a plastic bottle—changed weekly). | Anxiety | ↓ |
Learning | ↑ | ||
Brain size | ↑ | ||
[99] | 50 haphazardly placed 50 mm lengths of artificial Elodea canadensis | Body length | ↓ |
Rate of learning | ↑ | ||
[100] | Artificial plants | Initial time to solve maze task | ↓ |
Rate of learning | ↑ | ||
Memory retention | ↑ | ||
[103] | Plastic grass or plastic leaves | Number of eggs | ↑ with plastic grass; no effect with plastic leaves |
Number of fry (6 dpf) | ↑ with grass when parents were 110 or 160 dpf; ↑ with leaves when parents were 173 or 180 dpf | ||
Survivability of fry (6 dpf) | No effect | ||
[104] | Gravel, plastic ‘ruin’, three submerged plastic plants (two 10 cm tall and one 20 cm tall) | Levels of reactive oxygen species in response to unpredictable chronic stress | ↓ |
[105] | Four or five submerged plastic plants | Aggression | ↑ |
Latency to feed | ↓ (one wild strain only) | ||
Shoaling distances | No effect | ||
[35] | One artificial plant, one upturned flower pot and aquarium backing with blue seascape design on rear tank wall | Aggression | ↑ |
Body length | ↓ | ||
Fertilisation success | No effect | ||
Number of eggs | No effect | ||
[34] | Three groups of 12 opaque black glass rods, 50 mm, 100 mm and 180 mm in height | Time for aggression levels to settle. | ↑ |
Activity | No effect | ||
Cortisol | No effect | ||
Shoaling density | No effect | ||
Space use | No effect | ||
[106] | 12 strips of plastic bag in a 3 × 4 arrangement to simulate vegetation | Aggression | ↓ |
Food monopolisation | ↓ | ||
[107] | Three artificial plants (15.24 cm tall, moneywort imitations) and aquarium gravel | Aggression | ↓ |
Fecundity | No effect | ||
[108] | Refuge created by partial wall | Aggression induced by exposure to lead | ↓ |
↑ = increase; ↓ = decrease.