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How much water to take out in water change, and otocinclus

Country joe

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My tank is a Juwel rio 125, my fish stocking is, 6 black phantom tetras, 8 Harlequin Rasboras, 12 green neon tetras, and 8 glowlights regarding water changes, I know there are lots of different opinions, but I like doing them once a week, with the amount of fish in my tank which do you think would be the one to do 25% or 50%.
I'm hoping to introduce either 2 or 3 otocinclus but have read they are very subseptical to changes in water, so would a weekly water change of 50% be too much for them ?
 
50% water change is better than 25% because it removes half of the harmful stuff in the water. If you only do a 25% water change, you leave 3/4 of the harmful stuff behind.

When the catfish have settled into the tank, they are fine with 90% water changes as long as the new water has a similar chemistry (pH, GH & KH) and temperature to the old water, and as long as the new water is free of chlorine/ chloramine before it's added to the tank.

It can take several days to a month or more for fish to settle into an aquarium. It just depends on how much difference there is in the different water (from where they came from compared to your tank). If they are acting normally and feeding regularly, then they have usually settled in.
 
My tank is a Juwel rio 125, my fish stocking is, 6 black phantom tetras, 8 Harlequin Rasboras, 12 green neon tetras, and 8 glowlights regarding water changes, I know there are lots of different opinions, but I like doing them once a week, with the amount of fish in my tank which do you think would be the one to do 25% or 50%.
I'm hoping to introduce either 2 or 3 otocinclus but have read they are very subseptical to changes in water, so would a weekly water change of 50% be too much for them ?
Hello Country. Change half the tank water once a week and keep your feedings to every other day, just as much as the fish will eat in a couple of minutes. Small water changes leave most of the pollutants in the water and the fish are continuously adding more waste. Food is the source of water pollution, pure and simple. Keep the food to a minimum and remove and replace half the water every week, no slacking. Do these two things, and you'll keep a healthy tank with healthy fish. It's really this simple.

10
 
50% water change is better than 25% because it removes half of the harmful stuff in the water. If you only do a 25% water change, you leave 3/4 of the harmful stuff behind.

When the catfish have settled into the tank, they are fine with 90% water changes as long as the new water has a similar chemistry (pH, GH & KH) and temperature to the old water, and as long as the new water is free of chlorine/ chloramine before it's added to the tank.

It can take several days to a month or more for fish to settle into an aquarium. It just depends on how much difference there is in the different water (from where they came from compared to your tank). If they are acting normally and feeding regularly, then they have usually settled in.
Thanks Colin, 50% it is.
 
they are fine with 90% water changes as long as the new water has a similar chemistry (pH, GH & KH)
Regular large water changes will keep tank water parameters similar to tap water. Smaller, and especially infrequent water changes allow the parameters to drift away from tap water parameters.
 
As long as the parameters are similar, you cannot change too much water. I actually love doing water changes, the bigger the better (within reason), because they're good for the fish. After a big water change they'll be more active, and hungrier (appetite is linked to nitrates, the lower the nitrates, the bigger the appetite).

As a minimum, change enough to keep the nitrates from rising every week. You may get away with 25% with your stock level, but I'd do 50% anyway, because that's even better.
 
They sell them in 5s at my local shop, will think about, but I don't want to overload my tank.
5 won't overload your tank, and they'll be healthier than 2 or 3. Otos really do need numbers. They live in groups of hundreds and even thousands, and 5 isn't even enough, but it'll be much better than 3.

Be careful buying them. Don't buy any with sunken bellies. And if you don't clean the back and side glasses they'll have a better chance, if there's some biofilm / algae available for them when you get them.
 
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Hi,
Is it okay to use hot water in a mixer tap to the aquarium, I have a combi boiler, as I've read not to use tap hot water, and instead boiling kettle water,
 
With a combi boiler you can use hot tap water. With this system, hot water is made on demand from mains cold water.

It's the system where hot water is stored in a cylinder in the airing cupboard and as hot water is taken out it is topped up from a header tank in the attic that should not be used, due to possible contamination of the header tank.
 
I live dangerously and mix hot and cold for water changes by hose. There have been no problems from that. I know the possible issues from a hot water heater, but for 9 months of the year, my tap is in the single digits celsius.

I think of fish like Otos as cells, not as individuals. A full Oto starts at about 10, for a tiny one. A medium aquarium oto (or cardinal or other shoaler) is 20 fish. It can be very hard to feed 10 Otos in some tanks, so I have none here. You need a good sized tank with a decor to generate biofilm for those guys. I love them, but they are challenging little things.
 
I live dangerously and mix hot and cold for water changes by hose. There have been no problems from that. I know the possible issues from a hot water heater, but for 9 months of the year, my tap is in the single digits celsius.

I think of fish like Otos as cells, not as individuals. A full Oto starts at about 10, for a tiny one. A medium aquarium oto (or cardinal or other shoaler) is 20 fish. It can be very hard to feed 10 Otos in some tanks, so I have none here. You need a good sized tank with a decor to generate biofilm for those guys. I love them, but they are challenging little things.
I would just be keeping 5, and I know it can be difficult to get them to eat suitable food tablet, but I will try, but I have algae, in the tank, my good fish shop, not pah, said they never have any bother with them, but they would say that, but I will give them a go.
 
With a combi boiler you can use hot tap water. With this system, hot water is made on demand from mains cold water.

It's the system where hot water is stored in a cylinder in the airing cupboard and as hot water is taken out it is topped up from a header tank in the attic that should not be used, due to possible contamination of the header tank.
In my old house i tried doing a water change with the kitchen mixer tap, the house didn't have a combi, the fish were fine but it wiped out pretty much all of my plants, still to this day i struggle to ge tgood growth in the tank.
Thankfully our current house has a combi, makes water changes so much easier
 

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