Classroom tank transitions without unduly stressing fish

  • #1
I would like to add a fish tank to my middle school science classroom. I've seen fish in classrooms before, so I know it's possible, but there are a few logistics I am stuck on:
  • Transport stress. I'm currently working on cycling a tank at home so I can get some experience under my belt and the eventual fish can get settled while I have lots of time to observe them. However from what I've read, moving fish tanks is somewhat complicated, requires completely emptying them, stresses both fish and plant roots, and can re-upset the nitrogen cycle. The fish will only live in the classroom during the school year and I would need to take them home for summer and winter breaks. Can I use one tank that I move between locations, or do I need a tank at each location, or how do people do this?
  • Weekends/nights: I won't physically be there to feed fish at night, so does that mean I can only keep day-active species, or will night-feeding species adjust if there's a strong routine? Do I need a timed-release food system for the weekends? I've read that fish can handle not being fed for a few days during a vacation, but would it be stressful to have a 2-day gap like that every single weekend?
Another question I'm curious about: Suppose my students wanted to do an experiment with the fish that would work best in a separate, smaller tank. For example, teaching a fish to swim through a maze. Would it be too stressful to a fish to be placed into a separate tank for an hour every day then put back in the original tank? Let's assume the tank is smaller enough that it can be filled with water from the original tank. I'm guessing the answer is probably, "Yes, too stressful," but I'm curious if anyone has experience with anything like this. It would be nice if we could interact with the fish in scientific ways, but any experiments obviously need to be humane.

Other information in case it's useful:
  • 29 gallons is the proposed tank size. (Larger than that I'm not confident my home furniture and the built-in lab counters can support the weight...)
  • Water from my house tap (publically available data matches the low-quality strip test Petsmart did for me):
    • Not chlorinated or treated, other than coarse filtration. Source is a local stream.
    • Total hardness: 56-174 ppm, median 142 ppm
    • pH 7.5-8.3, median 8.1
    • Almost imperceptibly low in agricultural contaminants.
  • Water from my classroom tap:
    • Water is not chlorinated (that surprised me to learn.)
    • City water parameters for total hardness are either 190-500, average 270 ppm or 240-250, average 245 ppm, depending whether it's sourced from surface or ground-water. No idea which supplies my classroom, but the low-quality test strip Petsmart did for me suggested the hardness was greater than 300 ppm. So, let's just say it's "hard"...
    • Couldn't find public data for city pH parameters, but that inaccurate test strip suggested pH above 8.4, which makes sense given the hardness.
    • Lots of agricultural runoff including some nitrates and nitrites.
  • Commute time from home to school is 45 minutes.
  • Proposed stocking:
    • 6 mollies. (Why? I want 6 fish of distinguishable colorations so each class could have their own fish, and I gather mollies can be kept as mixed colors because they are not obligatory shoaling fish. Also they like hard, alkaline water.)
    • 2 blue/3-spot gouramis (Why? Purely for variety and maybe to help eat molly fry. I'm flexible here.)
    • 1 bristlenose or clown plecostomus (Why? I want a fish that is cleary, visibly adapted to a primarily plant-based diet as a talking point.)
    • I would love to keep java or kuhli loaches, because they're awesome, but they seem incompatible with the hard, alkaline water. :'(
    • Plants
  • Hoped-for pedagogical talking points:
    • Ecosystem/population stability, especially the cycle of life and death. (E.g. if livebearers give birth and all the fry get eaten, that's actually perfect.)
    • Energy transfer starting with photosynthesis and moving up a food chain with individual organisms having specific diets. (It's a common misconception in middle school that a starving herbivore would turn into a predator to survive.)
    • The scientific method, including the ethics of experimenting with living things.
    • Etc. The chemical reactions that happen during the nitrogen cycle could be a great talking point too, but it's invisible, and I'm hoping the tank will cause some questions to arise naturally. Anything a student asks of their own accord is infinitely more interesting than something the teacher wants them to care about, haha.
Wow, that was a lot of words! I appreciate any and all advice. This will be my first time keeping fish since I was a tiny kid and completely oblivious to the details.
  • #2
I know a lot of people have aggression issues with mollies, I'd be concerned with keeping them with gourami.

No actual experience, just what I've read. Platies are supposedly less aggressive.
  • #3
Hi Loica
Welcome to fishlore.

You are doing the right thing setting up a tank at home.

What county are you in ? Australia here.

To answer some of your questions.
Fish are transported in plastic bags. Every day thousands are in the post. 24 hours in a bag no problem. A hot water bottle in a polystyrene box full of plastic bags is how we take fish to auctions. Extreme weather cold or hot will need planing.

The cycle lives ON hard surfaces, mostly on the filter but ALSO on all hard surfaces in a tank . Moving a cycle requires all hard surfaces to be kept wet / damp . In a classroom sponge filters will be best although not pretty they can be moved easy . They are a simply design . You already have a tank at home. Running multiple filters in one tank means you can move filters around in buckets easy.

Moving Plants .

Plants that have roots glued to rocks or wood. Plants that float and plants in terracotta pots will all move easy . However slightly different water parameters will shock plants, some species of plants much more than others. Suggest no plants are needed in aquarium tank gravel . Terracotta pots or any container are the key for your situation. Floating plants that grow fast are weeds in the real world. A handful of floating plants now will mean you have more than enough for multiple tanks.

We all should only feed once a day . Many of us feed far to much. Molly or suggested platy fry will look after themselves in an established tank. Breeding live bearers is not a challenge. Many office tanks have weekends often including long weekends. I have left adult fish ten days without food. Feeding to much food kills fish. You will need to supervise feeding in a classroom. The fish food will need to be locked up. Even the room cleaners will feed your fish at night or at random times if they find the food, a bad thing.

Moving fish around to work / play/ experiment with them. Different water parameters are very very stressful. It would be better to have a fish in a separate tank/ container permanently or at least for weeks at a time. Limit the idea of moving from tank to tank / container to container . That I believe is a bad idea. It would in theory be possible to move fish with their own water.

Suggest stocking
Platies are smaller. They can handle a wider range of temperature and water parameters. Skip the 3 spot gourami in favour of a smaller more peaceful honey gourami ( or group)
You will have to learn about culling unwanted fry. In the beginning of the hobby every fish is sacred , you will learn soon fish eat fish. In order to provide the best environment for a few adult fish you can’t keep every fry alive. I am serious when I use the two names for live bearers. The million fish, and the most dangerous fish.

Work on the assumption that all water needs a de chlorinator. Don’t over think keeping fish.

One bristlenose pleco only per tank.

Ethics of fish keeping.
This is going to be extremely difficult to write about in open channel . Not only are young kids reading this but we all come from different countries with different attitudes etc. You seem to be smart enough to read between the lines ? I do warn you that you are going to have multiple tanks/ containers in no time. Limit the number of fish species is my suggestion.
  • Thread Starter
  • #4
I'm in the USA, and yes, I will definitely be keeping the fish food in one of the locked cupboards. Not something I want over-eager hands messing with... Thanks for your suggestion of keeping the plants in pots within the tank. That does sound like it would make moving them without disturbing their roots easier. For unwanted fry, I gather you are saying their number will outpace the dietary needs of larger fish? I've heard stories of live-bearing fry getting quickly devoured, but obviously I'm no expert. I do not wish to keep an exponential number of fish, so I will have to learn whatever needs learning about keeping the numbers stable. Good thing population stability is a topic in my class...

For intraspecies molly aggression, I've heard it depends on the ratio of males to females. Not sure if that's at all relevant to interspecies aggression.
  • #5
Im fine with the stocking and the tank size, but taking fish in and out of there tank to do 'experiements' will most likely be quite stressful for the fish, having loads of eager faces staring tapping on the tank isnt gonna be fun for the fish. Try to keep as class pet not so much as an expereiment.

You can feed each day mon-fri and skip sat and sun, the fish will be fine, as for school holidays you can get auto feeders or come and feed them every couple days.

Those fish are fairly hardy and should be fine without food for around 7-12 days, if you gonna leave them for a while give a good water change and feeding before leaving (school holidays) and then feed and water changes when school term starts again.

Best of luck :)
  • #6
Yes adult fish including juveniles will eat fry. Depending on hiding places only a very few will survive.

As far as experiments / training of fish . Do whatever the law allows in your state . And you feel comfortable doing. Having taken bags of fish for a 300 km / 190 mile car ride this week only to almost give them to a shop then pay full price for other small bags of water with adult fish in them I am not going to judge anyone. It is probably better for kids to learn hands on what is acceptable practice in a group situation?
You could mention to the students how food animals are raised even in America?

Yes the male female ratio of fish can have some bearing on aggression. It is also in the nature of some species to be more willing to share a very limited puddle of water. In nature fish can swim away. In an aquarium perhaps picking a less aggressive species like mentioned earlier ( platies) is going to be easier on the eye.
I do not enjoy seeing a fish chased to death. Or a fish having its fines nipped down smaller and smaller until it can not swim with enough speed to get away.

The whole concept of a community tank is a human construction and has nothing to do with how fish survive.
  • #7
I always thot breeding experiments with different color neocardina shrimp would be interesting. They breed quickly enough that you could put various colors together and see what kind of offspring you get.

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