Do Workplace Fish Tanks Influence Employee Wellbeing and Cognitive Performance? An Embedded Mixed-Methods Study

Figures & data

Figure 1. Overview of study design: (a) embedded mixed methods design, (b) design of Trial A, (c) design of Trial B.

Table 1. Outcomes assessed in Trial A and Trial B.

	Outcome	Assessment method
Trial A	Mood: positive and negative affect, perceived arousal	Positive and Negative Affect Schedule (PANAS; Watson et al., 1988), consisting of 20 items (10 per scale) relating to positive and negative affect (e.g., “interested” or “ashamed”). Perceived Arousal Scale (PAS; Anderson et al., 1995) consisting of 24 items relating to low and high arousal (e.g., “drowsy” or “active”). Responses given on a scale of 1 (“very slightly or not at all”) to 5 (“extremely”). Negatively worded items were reverse scored (PAS only), and responses summed for total scores; higher scores indicate higher levels for each state (Cronbach’s α = 0.77–0.92).
	Physiological stress: heart rate, blood pressure, salivary cortisol	Heart rate measured using a Polar® H7 heart rate sensor to obtain real-time heart rate measurements via smartphone application (Polar Beat, Polar Electro®). Systolic and diastolic blood pressure measured using an automatic blood pressure monitor (Omron M3, Model HEM-7131-E), using the same arm for each measurement with each participant. Salivary cortisol analyzed using commercial ELISA kits (Enzo Life Sciences, Cortisol ELISA kits, ADI-900-071 and ADI-901-071) following the manufacturer protocol. Samples were collected via the passive drool technique, immediately placed on ice, and stored at –80°C. Directly before analysis they were defrosted and centrifuged (2 min, 4°C, 14000 rpm); steroid displacement reagent was added as per manufacturer instructions and samples were diluted at a ratio of at least 1:1 standard diluent to sample. To account for inter-plate variability, all samples for each participant were analyzed on the same plate, excepting one that was re-run due to readings indicative of contamination. All outcomes were measured once at rest, with the participant in a seated position.
	Cognitive performance: inhibitory control and working memory	Inhibitory control measured using the Stroop Color-Word Task (SCWT; Stroop, 1935). Participants were required to state the color of 100 color words printed in the wrong color (e.g., the word “brown” in red ink), thus requiring overriding of the automated response (reading the word) with a less automated response (saying the color). Number of errors (SWCT-Errors) and time taken in seconds (SCWT-Time) were recorded. Working memory assessed using the digit-span forwards (DSF) and backwards (DSB). Participants heard a list of digits (e.g., “8, 9, 3”) and repeated them back either in the same direction (DSF) or reversed (DSB). If successful, the length of the list was increased by one (max = 9 digits) until recall failed on two subsequent trials. Scores for each were the length of the longest list correctly recalled. Both tasks have been used to assess attentional capacity in past research (Ohly et al., 2016).
Trial B	Psychological wellbeing: depression, anxiety, stress, job-related affective wellbeing	The Depression Anxiety Stress Scales (DASS; Lovibond & Lovibond, 1995), consisting of three 14-item scales. Participants indicated how much each statement (e.g., “I found myself getting upset by quite trivial things”) had applied to them over the past week, from 0 (“Did not apply to me at all”) to 3 (“Applied to me very much, or most of the time”). The short Job-related Affective Wellbeing Scale (JAWS; Van Katwyk et al., 2000), consisting of 20 job-related emotion statements (e.g., “My job made me feel angry”). Participants indicated how much they had experienced each emotion over the past 30 days, from 1 (“never”) to 5 (“extremely often”). The high pleasure-high arousal (e.g., “enthusiastic”), high pleasure-low arousal (e.g., “calm”), low pleasure-high arousal (e.g., “angry”), low pleasure-low arousal (e.g., “depressed”) subscales were also calculated. For each questionnaire, negatively worded items were reverse scored (JAWS only) and responses summed for a total score so that higher scores indicated greater experience of that state (Cronbach’s α = 0.74–0.94).
	Physiological wellbeing: heart rate, blood pressure	Heart rate and blood pressure were measured as in Trial A. Salivary cortisol is highly influenced by extraneous variables, so was not assessed in Trial B.
	Job satisfaction (covariate)	The Job Satisfaction Survey (JSS; Spector, 1985). Participants indicated how much they agreed with 36 statements (e.g., “I feel I am being paid a fair amount for the work I do”) on a 6-point scale, from 1 (“disagree very much”) to 6 (“agree very much”). Negatively worded items were reverse scored and all responses were summed for a total score, with higher scores indicating higher levels of job satisfaction (Cronbach’s α = 0.88). Subscales of the JSS were not calculated.

Note: Effects of watching fishes on cognitive performance were expected to be transient, so cognitive outcomes were not assessed in Trial B.

Table 2. Participant characteristics for original and follow-up samples.

	Original sample (n = 57)			Follow-up (n = 13)
	Trial A (n = 30)	Trial B (n = 27)	Total (n = 57)
Campus
1	22 (73%)	21 (78%)	43 (75%)	10 (77%)
2	8 (27%)	6 (22%)	14 (25%)	3 (23%)
Job role
Academic	9 (30%)	8 (30%)	17 (30%)	6 (46%)
Research student	8 (27%)	7 (26%)	15 (26%)	3 (23%)
Other	13 (43%)	12 (44%)	25 (44%)	4 (31%)
Gender
Male	8 (27%)	8 (30%)	16 (28%)	4 (31%)
Female	22 (73%)	19 (70%)	41 (72%)	9 (69%)
Age in years	39.73 ± 11.05	41.41 ± 11.88	40.53 ± 11.38	40.54 ± 11.29
Fish guardianship
Any time	21 (70%)	20 (74%)	41 (72%)	10 (77%)
Childhood	15 (50%)	15 (56%)	30 (53%)	4 (31%)
Adult – not current	5 (17%)	7 (26%)	12 (21%)	3 (23%)
Adult – current	4 (13%)	4 (15%)	8 (14%)	3 (23%)
Dropout	0	5 (19%)	–	–

Note: Data for categorical variables are frequencies and percentages; data for continuous variables are means and standard deviations. Participants could provide multiple responses to questions regarding fish guardianship.

Figure 2. Boxplots showing (a) positive affect, (b) negative affect, (c) systolic blood pressure, and (d) time taken to complete the Stroop Color-Word Test (SCWT) at pre-test and post-test for each condition. Data are 20% trimmed means (black circles), median, interquartile range, and outliers (white circles). n = 30, *p < 0.05, ns = not significant.

Figure 3. Boxplots showing (a) total job-related affective wellbeing (JAWS), (b) high pleasure-high arousal (HPHA) subscale, and (c) high pleasure-low arousal (HPLA) subscale after engagement in each condition. Data are means (black circles), median, interquartile range, and outliers (white circles). n = 24, *p < 0.05, ns = not significant.

Table 3. Summary table of themes developed via reflexive thematic analysis.

Theme	Description	Example quotations
Live fishes are more engaging than videos	Watching live fishes was viewed as a calming activity, which also provided interest and stimulation. By comparison, the video was seen as lacking “something,” despite being recognized as visually similar to the aquarium. Several participants conveyed a connection to the live fishes that was not present in the video. Some participants commented on the sound of the aquarium, and one commented on the smell, so the lack of a quantitative effect may have been due in part to factors associated with the presence of a fish tank other than watching the fishes.	“it doesn’t make sense why watching a video or watching them live would be any different, but I definitely felt more engaged with watching the live fish than the video” (Participant 5, Focus Group 1, Trial A) “although it was interesting even in the video to watch their behaviour, yeah it’s not that same as watching live fish or live animals is it?” (Participant 8, Focus Group 4, Trial B) “I started imagining they had little communities and there was like a bully fish and there was a big fat fish, and it was like ‘what’s going on with them?’” (Participant 10, Focus Group 3, Trial B)
It was good to get out of the office	Participants had to walk from their office to the testing location, and this appeared to provide them psychological distance from their work. This in itself had benefits, with some likening it to the difference between taking a break and eating lunch at their desk. Some participants felt the presence of an aquarium in a break room opposed to an office may be more effective due to this reason. However, many also felt that the presence of a fish tank or video within the office may be effective at providing momentary relief from work, provided it was large enough to promote a sense of immersion.	“it was good to come to somewhere totally different where I wasn’t going to meet anybody from my office or anybody who was going to be asking any questions or starting up any conversations, it was absolutely separate which was good” (Participant 8, Focus Group 4, Trial B) “I think having the ability to go away somewhere specific and kind of yeah, immerse yourself and have a bit more of an experience would make it a bit more novel and a bit more unique” (Participant 1, Focus Group 1, Trial B)
Just taking ten minutes was beneficial	Several participants expressed that taking time out of work was an unfamiliar concept, with the idea of “doing nothing” (as in the control) being completely alien. Some found this a pleasant and relaxing experience, whereas others found it stressful and spent the time thinking about work and feeling guilty about taking time away from their desk; the latter group expressed a clear preference for the live fishes or video as it gave them a point of focus. Being part of a research project helped alleviate this guilt as it allowed participants to schedule sessions into their diary and so they felt they could better justify their use of time. Thus, some participants appear to have found benefit from all three conditions, perhaps partially explaining the lack of an effect in the quantitative results.	“I actually found it quite stressful sitting staring at a blank wall because I started to think about all the things I should be doing and where I should be and what I should be catching up on” (Participant 4, Focus Group 1, Trial A) “having that time out, even just for that short time every week I think really helped, and it was definitely worthwhile” (Participant 9, Focus Group 3, Trial B) “the thing that I found most useful from the experiment was allocating the time on my calendar where I was out of my office, I was doing something and it can be seen that I was doing something and I wasn’t expected to answer emails or do anything else” (Participant 7, Focus Group 1, Trial A)

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