#tropicalfish

The Water Change Myth Everyone Believes!

One of the biggest myths in the aquarium hobby is that large water changes are always dangerous. In reality, it's not the percentage of water you change that matters most, it's how closely the new water matches the water already in your aquarium.

In this video I explain why the common "25% water change every week" recommendation isn't a universal rule. While there are situations where changing around 25% makes sense, such as gradually reducing nitrate levels, many people repeat the advice without understanding why. Over time, that has led to the misconception that anything larger will automatically shock your fish.

The truth is that many aquariums can safely handle much larger water changes when they're done correctly. Matching the temperature of the new water, using a dechlorinator, and making sure key water parameters are reasonably similar can make a huge difference.

In my own heavily planted aquariums, the Total Dissolved Solids (TDS) stay surprisingly close to my tap water because the plants help maintain stable water conditions. That means I can perform larger water changes when needed without causing problems. Every aquarium is different though, so it's always worth checking your own parameters rather than relying on general advice.

Affordable tools like a TDS meter, digital thermometer, pH meter, GH/KH test kit, and a standard aquarium liquid test kit can help you compare your aquarium water to your tap water before carrying out larger water changes. Spending a few minutes checking your parameters is far more useful than blindly following an old rule that may not apply to your setup.

The goal isn't to encourage everyone to do massive water changes. It's to show that one larger water change can often be a perfectly reasonable option if your schedule doesn't allow for several smaller ones. Understanding why you're changing water is far more important than sticking to an arbitrary percentage.

125-Day Planted Aquarium Update (Inert Sand, No CO₂, No Root Tabs)

This is my 70-litre (18 US gallon) planted aquarium, now 125 days old and home to two honey gouramis, nine lambchop rasboras, and a colony of mixed-line Neocaridina shrimp.

The tank uses inert sand with no root tabs, a Seachem Tidal 35 filter, and a Chihiros B Series light. I moved the honey gouramis over a couple of weeks ago, and they've settled in perfectly. One has claimed the back left corner, the other the back right, and one has already started building a bubble nest.

The lambchop rasboras are doing well too, and I'm thinking about increasing the group soon. I was originally considering adding Panda Corydoras, but I'm now leaning more towards moving my ember tetras and pygmy corydoras over from another aquarium instead.

The "Skittles" Neocaridina colony originally included red, orange, yellow, and blue lines. Apart from the reds, most have gradually lost their colour over time, although they still produce some really interesting wild-type shrimp.

Overall, I'm really happy with how the plants are progressing. I recently added an Echinodorus 'Aflame', which is supposed to be an easy red sword plant, so it'll be interesting to see how it performs over the coming months.

The standout plant has to be the Aponogeton ulvaceus. Most nurseries recommend growing it in a nutrient-rich substrate, yet it's thriving in plain inert sand and has already produced both runners and a flower.

Several other plants that are usually considered heavy root feeders are doing well too, including all of the Cryptocoryne species and most of the Echinodorus swords, although my Echinodorus 'Tricolour' is still taking its time.

The houseplants are starting to fill in nicely as well, with spider plants, Epipremnum, and Philodendron all taking advantage of the warmer summer weather.

The only real challenge at the moment is algae.

I'm fairly sure it's being fuelled by excess organics released as the Centurion wood decomposes, but thankfully it's gradually becoming less of an issue as the tank continues to mature.

PLANT LIST

125-Day Planted Aquarium Update (Inert Sand, No CO₂, No Root Tabs)

This is the latest update on my 70-litre (18 US gallon) planted aquarium, now 125 days old, and I'm really happy with the progress it's made so far. The tank is home to two honey gouramis, nine lambchop rasboras, and a mixed-line "Skittles" colony of Neocaridina shrimp. Despite using inert sand with no root tabs, the aquarium continues to grow a wide variety of plants surprisingly well under a Chihiros B Series light with filtration provided by a Seachem Tidal 35.

The honey gouramis only moved into this aquarium a couple of weeks ago, but they settled in almost immediately. One has claimed the back left corner while the other has taken over the back right, and one has already started building a bubble nest. The lambchop rasboras are thriving too, and I'm considering increasing the size of the school. I originally planned to add Panda Corydoras, but I'm now leaning towards moving my ember tetras and pygmy corydoras into this aquarium instead.

The mixed-line Neocaridina shrimp are still breeding well. The colony originally included red, orange, yellow and blue shrimp, although apart from the reds, many of the other colour lines have gradually faded over time. Even so, they continue to produce some really interesting wild-type shrimp with unique patterns and colours.

One of the newest additions is an Echinodorus 'Aflame', which is often recommended as an easy red sword plant. It'll be interesting to see how it develops over the coming months. The real star of the aquarium, though, has to be the Aponogeton ulvaceus. It's commonly recommended for nutrient-rich substrates, yet it's thriving in plain inert sand, producing long flowing leaves, runners, and even a flower.

Several plants that are usually described as heavy root feeders are also growing far better than many people would expect. The Cryptocoryne species and most of the Echinodorus swords are doing extremely well, although the Echinodorus 'Tricolour' seems to be growing more slowly than the others at the moment.

The emersed houseplants are beginning to fill in nicely too. The spider plants, Epipremnum, and Philodendron have all put on noticeable growth as the warmer summer weather has arrived, helping to create a more natural riparian look above the aquarium.

The biggest challenge right now is algae. I'm fairly sure it's being fuelled by excess organics released from the Centurion wood, which started decomposing much faster than I expected after it was added to the tank. Thankfully, the problem is slowly fading as the aquarium continues to mature.

I Removed My Guppies… Everything Changed (Planted Aquarium Update)

What happens when you remove the main predator from a planted aquarium? That's exactly what I'm finding out after taking the guppies out of one of my tanks and giving them to a friend for his breeding project.

Within just a couple of weeks, the ecosystem has already started changing in some really interesting ways. The biggest difference has been the sudden explosion in the flatworm population. Although they look similar to planaria at first glance, I believe they're harmless flatworms because their heads have a different shape. It seems very likely that the guppies had been quietly controlling their numbers without me ever noticing.

I've also seen a huge increase in what I believe are freshwater copepods, although I'm not completely certain of the identification. Whatever they are, their population has grown dramatically since the guppies were removed, suggesting they were another natural food source that the fish had been keeping in check.

Freshwater limpets are still present too, although I haven't noticed any significant change in their numbers just yet. It'll be interesting to keep watching over the coming weeks to see if they also respond to the absence of the guppies.

The Neocaridina shrimp continue to thrive as usual. Despite keeping guppies with them for years, I've never actually witnessed the guppies eating either adult shrimp or shrimplets. Even so, I'm curious to see whether the shrimp population grows more quickly now that one potential predator has been removed from the aquarium.

Of course, ecosystems are always changing, and this experiment probably won't stay this way for long. I've recently introduced medaka ricefish fry into the tank and, as they grow, they'll almost certainly begin feeding on some of these tiny invertebrates. That should shift the balance of the aquarium once again and create an entirely new food web.

It's a great reminder that every species in an aquarium influences the ecosystem, even in ways we don't always notice. Sometimes removing just one fish can trigger a chain reaction that affects countless other organisms living in the tank.

Why Seeded Aquariums Still Need To Cycle!

Does adding mature filter media instantly cycle a new aquarium? Not always.

One of the biggest myths in the aquarium hobby is that squeezing out a mature filter or moving established filter media guarantees an instant cycle. While it can definitely speed things up, the reality is much more complicated.

Not all of the microorganisms responsible for biological filtration are the same. Different groups have different environmental preferences, ammonia tolerances, and growth rates. A mature aquarium with virtually no ammonia may be dominated by ammonia-oxidising archaea, while a brand-new aquarium experiencing elevated ammonia often favours ammonia-oxidising bacteria instead. This means the microorganisms you're transferring may not be the ones best suited to the new tank.

Water chemistry also plays a huge role. Differences in pH, temperature, alkalinity, hardness, and even phosphate availability can all affect how efficiently these microorganisms work. Moving mature media from a cool, hard water aquarium into a warmer, soft water setup may provide far less biological filtration than many people expect.

Heterotrophic bacteria add another layer of complexity. They can temporarily reduce ammonium by incorporating it into new cells as they grow, but they also require an organic carbon source. Since brand-new aquariums usually contain very little organic matter, their contribution is often smaller than people realise.

Another common misconception is that almost all beneficial microorganisms live inside the filter. In reality, large populations also colonise the substrate, plants, rocks, wood, decorations, and every other surface in the aquarium. Depending on the setup, transferring mature filter media may only move a fraction of the established microbial community.

Dissolved oxygen matters too. Most of the microorganisms responsible for nitrification need plenty of oxygen to work efficiently. If the new aquarium runs warmer with less surface agitation, like many betta tanks, the transferred microorganisms may not perform as well as they did in the donor aquarium.

My Aquarium Is 840 Days Old… Here's How It's Doing...

Over the last month it's had a couple of major upgrades, with the biggest being a new Seachem Tidal 55 filter and a Seaoura SR659 light.

So far, both have been performing really well, and I'm happy with the improvements they've made.

I also recently mentioned that my Siamese algae eater had started eating some of my plants, but thankfully that seems to have stopped. It may have been stress caused by last week's heatwave.

It also looks like one of my zebra danios is carrying eggs.

There are plenty of fish in the tank that would happily eat any fry, but there are also lots of dense plants for them to hide in, so it'll be interesting to see if any manage to survive.

Other than that, all of the fish are doing well, and the shrimp population continues to thrive.

I'll be taking down one of my shrimp tanks soon to make room for another aquarium, and when I do, all of the cherry shrimp will be moved into this tank to give the Neocaridina colony an even bigger boost.

The plants are all growing well too.

I thought I'd removed every Nymphaea lotus 'Green' bulb over a year ago, but at least one must have survived because it's started sending lily pads up to the surface again.

The houseplants with their roots growing in the aquarium are doing really well as well.

I recently upgraded the pothos and spider plant to a new grow light, and both have already started putting out plenty of fresh growth.

The pothos has even sent out a long runner, which I'm training along the light to create a natural green backdrop behind the aquarium.

Overall, I'm really happy with how this tank is developing, and apart from that brief issue with the Siamese algae eater, everything seems to be heading in the right direction.

My Planted Community Aquarium Is 840 Days Old… Here's How It's Doing...

Today marks 840 days since I set up my 160 litre (40 US gallon) planted community aquarium, so I thought it was a good time for another update.

Over the last month, this aquarium has had a couple of major upgrades. The biggest changes were replacing the old filter with a Seachem Tidal 55 and upgrading the lighting to the Seaoura SR659. So far, both upgrades have been performing really well. The new filter is much quieter, provides excellent flow, and the new light has been encouraging healthy plant growth while giving the aquarium a brighter, more natural appearance.

I also recently shared that my Siamese algae eater had started eating some of my plants, particularly a few of my Echinodorus species. Thankfully, that behaviour now seems to have stopped. It may simply have been a temporary stress response caused by last week's heatwave, but I'll continue keeping an eye on it over the coming weeks to see if the behaviour returns.

Another interesting development is that one of my zebra danios appears to be carrying eggs. While there are plenty of fish in this aquarium that would happily eat any fry, there are also lots of dense plants, mosses and hiding places throughout the tank. If any fry do hatch, it'll be interesting to see whether a few manage to survive naturally without any intervention.

Apart from that, all of the fish seem to be doing really well. The shrimp population continues to thrive too. I'll actually be taking down one of my dedicated shrimp tanks soon to make room for another aquarium, and when I do, all of those cherry shrimp will be moved into this tank, giving the Neocaridina colony another big boost.

For anyone interested in the plants, I've included the full plant list in the video. Despite the brief issue with the Siamese algae eater, everything has been growing really well. One surprise was discovering that at least one Nymphaea lotus 'Green' bulb survived after I thought I'd removed them all over a year ago. It's now started sending lily pads back up to the surface, which was completely unexpected.

The houseplants growing with their roots submerged are also thriving. I recently upgraded both the pothos and spider plant to a new grow light mounted behind the aquarium, and they've already started producing lots of fresh growth. One of the pothos vines has even begun sending out a long runner, which I'm carefully training along the light to create a living green backdrop behind the aquarium.

This aquarium has now been running for well over two years, and it's always interesting to see how it continues to evolve. Plants mature, fish establish their own behaviours, shrimp colonies expand, and even unexpected surprises like dormant lily bulbs can appear months or even years later. That's one of my favourite things about keeping established planted aquariums—there's always something new happening.

Unboxing Two New Betta Fish For My Planted Aquariums!

If you've been following my aquarium projects, here's a closer look at the arrival of my two new betta fish and how I introduced them to their new homes.

Both bettas came from Alternative Aquarist, who breeds and sells bettas within mainland UK. Unlike many breeders who focus on producing specific strains through line breeding, she selects parents from different bloodlines with the aim of producing healthier, hardier fish. It's an approach I find really interesting, especially if it helps improve long-term health and reduce some of the problems associated with intensive line breeding.

The fish arrived well packaged with a heat pack that still had a little warmth left in it. Even so, we're in the middle of summer here in the UK, so temperatures have been high enough that the fish were never at much risk of getting cold during transit.

The first fish is a beautiful blue female betta. The second is a stunning copper male that shows some characteristics often associated with alien bettas, although he isn't bred as a true alien strain.

One thing some people may notice is that I didn't drip acclimate either fish. Instead, I moved them into their aquariums as quickly as possible. My reasoning follows the advice explained by Prime Time Aquatics. During shipping, carbon dioxide builds up inside the sealed bag, lowering the pH and keeping ammonia in its less toxic ammonium form. Once the bag is opened, carbon dioxide begins escaping, the pH starts to rise, and any ammonia present can become significantly more toxic. Because of this, I prefer to get shipped fish into clean, fully prepared aquariums as quickly as possible rather than leaving them sitting in shipping water for extended periods.

The important point is that both aquariums were fully cycled long before the bettas arrived. The biological filters were already established, water parameters were stable, and the tanks had been planted in advance so the fish could be introduced straight into mature, safe environments.

I also picked up a couple of mystery snails, which are completely new to me. They were banned in the UK until relatively recently, so I've never had the opportunity to keep them before. It'll be interesting to see how they do over the coming months.

The two bettas couldn't have had more different personalities. The blue female immediately started investigating absolutely everything in her aquarium. Within minutes she'd tried eating snails, sand, leaves, plant roots, and anything else that caught her attention. She also spotted the bloodworms almost instantly and devoured them within seconds.

The copper male, on the other hand, was much more cautious. Rather than rushing around the aquarium, he spent hours slowly exploring every corner of the tank. When I offered him bloodworms, he looked more confused than interested and ignored them completely, leaving most of them for the mystery snails to finish instead.

Thankfully, both fish settled into their new homes without showing any obvious signs of stress, which is exactly what I was hoping for. It'll be fun watching their personalities develop as they become more confident over the coming weeks.

For anyone wondering about the setups, each aquarium holds 30 litres (around 8 US gallons). I also chose not to include any hardscape. While rocks and wood can look fantastic, leaving them out gives the bettas as much uninterrupted swimming space as possible while allowing the plants to become the main feature as they continue to grow in.