I left my fish for five weeks!

[raylove]

I have many times left my fish for up to two weeks whilst away on holiday. I usually use an Eheim automatic feeder, give the tank a good clean before I go and everything usually runs smoothly.
Recently I was faced with a bigger problem as I went away for a mega 5 week holiday and I thought it was worth posting my experience.
My source water is 35ppm nitrate so usually I keep water changes to a maximum of 15% per week as I find that constantly upsetting the balance and spiking nitrate levels by performing larger changes causes a lot of issues. I know this goes against most thinking, but that has been my experience over 50 years of fishkeeping and my fish have done very well on this regime. I always use a gravel vac to remove as much waste during each change.
My current 55g is fully stocked with large tetras (African Long Finned, Congo), barbs, Red Scissortail, CAE etc.. plus a small group of Pygmy Chain Loaches.
Despite my usual practise, in the two weeks leading up to the holiday I performed 4 large water changes of up to 50% each time. My main aim was to thoroughly vacuum the gravel and I lifted and moved most of the plants to get at all areas, including parts that I wouldn't be able to get to and as a result I shifted a huge amount of dirt. Of course I cleaned the filter the day before leaving too. I cut the plants well back and bought some new ones.
As a result of these large water changes my nitrate was 30ppm by now compared to a typical level of 5 - 10ppm, but I felt I had no choice but to change that amount on this occasion. I do use BioNitratex in my filter to aid nitrate removel, however, I haven't always done so, so this can't be the sole factor in my tanks ability to neutralise nitrate. As it's often pointed out that plants use ammonia rather than nitrate, I guess I have anaerobic bacteria in there somewhere!
I set up my auto feeder. I have a DIY Co2 contraption and I recharged this the day before I went though I fully expected it to expire before I returned as normally this lasts 3-4 weeks.
I had arranged for someone to check the tank about half way through the time I was away. I didn't feel able to ask them to make any large water changes, but they were happy to do a brief gravel vac and as a result there was a water change of about 6 gallons at about 3 weeks in - a little over 10% in 5 weeks, so negligable, but at least some much got removed.
I'm now back, and this is what happened:
- Nitrate fallen back to 10ppm, so almost my 'normal' level. Phosphate was 0.25ppm. Normally I have zero and actually have to add this as otherwise my plants show signs of phosphate deficiency, so I was rather pleased to see that modest level showing up.
- Despite my checking that a full drum of food dispensed way more than 35 portions of food, the feeder was empty, so it looks like the fish were somewaht over fed during my absense. I have no way of knowing when it ran out.
- The fish all look fine. Well fed, active - totally normal. All accounted for too; no losses.
- There was a lot of algae on the glass, but elsewhere very little muck.
- It was a mixed picture with the plants. The CO2 generator was still just about running, but far less than usual, and of course no ferts had been supplied for 5 weeks. Some had grown very long and were blocking the light whilst others were stunted and some even covered in a thin fim of cyanobacteria. It look a mess but was actually fairly easy to clean up. Normally I would prune the plants rather carefully, but in the circumstances I simply removed all those that were stunted and those with the BGA on them. I then just pruned what was left. Some crypts looked a little sorry for themselves but I expect them to recover so I left them alone. I assume that it was this slowing up of plant growth that led to me being able to detect phosphate when normally I have to add this.
Basically a huge success! I was quite worried about leaving the tank unattended for so long but once I cleaned the glass, pruned the planted and vacuumed the gravel, everything looked perfect. I had assumed I would need to do a larger than usual water change upon my return, but I deceided against it. I of course cleaned the filter, but only did my usual 15% water change - there simply didn't seem to be any need to do more, and for the sake of stability, I decided to switch straight back to the usual routine. I will be relaxed about leaving my fish for an extended period in the future should I have to, but also knowing that they do perfectly well for such a long time makes me even more confident about leaving them for more normal breaks of 10-14 days.

 

[Wills]

Interesting situation, I'm similar with nitrates in my tapwater and I'm coming round to the idea of having ways of dealing with nitrate in the tank specialist media, terrestrial plants, even chemical filtration - resins and the like. Rather than big water changes. I think water changes are important but something weekly in the 15-20% range might be better if you can get your tanks to low nitrates with other sources.

 

[GaryE]

I am always thankful for clean water when I read these postings.

I had a friend who had homes in the south and north, and would go back and forth every 3 months or so. She had lived in the southern home before getting a job and a place here, and for a few years she ran her tanks in Mexico with automatic feeders, and seemed very successful. Once the job situation demanded it, she sold that house and brought her fish to Canada.

It was an odd way to fishkeep, with tanks unseen, but it worked.

 

[10 Tanks]

Hello ray. Am amazed the fish survived. A fish that's used to a 15 percent water change, suddenly getting several 50 percent changes would be enough to shock even the hardiest of fish. The sudden change in the water chemistry as a result of the large flush of pure water would upset the entire tank. You are one very, very fortunate tank keeper.

10 Tanks (Now 11)

 

[emeraldking]

Well, just know that a lot of fish are hardier than most people think. The frequency of water changes given at certain sites or books are just safe numbers. Which does mean that there's also a margin that's acceptable for those fish to survive in a captive environment.

 

[raylove]

Over the years there have been many times when I have stripped a tank down or maybe just decided on a rescape and mega clean. On those occasions I have performed much larger one-off water changes and there have been no issues (apart from the nitrate spike and minor things such as algae blooms that sometimes result). With good husbandry, strong plant growth etc..I'm not sure that the new water is actually any more 'pure' than the mature water in the tank.
Unlike reef fish, most freshwater fish are pretty well adapted to changes in water conditions. Most come from rivers that experience floods due to sudden rain or meltwater, or concentration of pollutants at times of drought. Just looking at my local river, sometimes it's bright and clean, a day later it's very murky and a week after that it's covered in an algae scum. In autumn it's choked with rotting leaves - but it's still full of thriving fish!
Don't get me wrong, I'm not advocating a cavalier attitude to water conditions, but if fish are happy and healthy then, for most species (not all!), the odd fluctuation isn't going to faze them. This is different (for instance) when buying new fish where the stress of being moved can be greatly exacerbated when coupled with a change in water parameters, or where your fish are not in peak condition. Provided they are then fluctuating conditions are perfectly natural - yes, avoid where possible but very unlikely to cause a problem if everything else is OK on those occasions where a change inevitable.
I had another experience recently when I plugged in a new timer for my lights. Due to the shape of the unit it inadvertently flicked the switch for the heater into the off position when I plugged it in. I only noticed this some 24 hours later and by then the temperature was 20C instead of the usual 25C. We had had a very cold night so I was surprised at how well the water had retained its heat, and also by how well the fish were doing - they were acting and eating absolutely normally. I switched the heater back on and over the next few hours the temperature returned to normal with no ill effects observed whatsoever. I'm sure they would have suffered if the low temperature had persisted for longer, but over one day the sudden drop didn't seem to be a problem - again, I'm not suggesting that this is desirable and obviously I do everything I can to maintain a stable temperature, however, when things went wrong I found it interesting that the fish were so adaptable, seeming to not even notice the issue.