Fresh Eyes

Over the time I’ve kept fish, I’ve set up a lot of aquariums. Working at Petco, I help set up even more.

The focus tends to shift to “how do I keep these fish alive?” or “how do I make this a functioning ecosystem?”

I recently helped my wife set up a betta tank. I ended up with a free 6 gallon cube, and she’d been wanting a betta for a while. Something that was hers.

It was hard for me to step back. She was fine with the filter and heater—no contest there—but she picked the plants and decor. No thoughts about long-term stability or balanced ecosystems. Just, “what would my betta like?”

It didn’t take long for her to get attached. Pebble settled in almost immediately. He patrols the tank slowly, moving between a few favorite spots. Sometimes it feels like he’s looking back through the glass at you.

Watching her get excited about those little behaviors, worrying about small things, and just falling in love with the fish is… familiar. It reminds me of my first tank.

Sometimes I forget why I keep fish.

Sometimes it takes fresh eyes to see the whole picture.

An Ocean in Miniature

A bonsai tree is a strange thing.

On the surface, it looks like decoration. A small, carefully shaped tree sitting on a shelf or a table. Something to admire.

But a bonsai isn’t something you buy. It’s something you maintain.

What you’re really looking at isn’t just a tree—it’s years of pruning, restraint, and patience made visible.

An aquarium is the same thing.

Just… wetter.

Starting a bonsai tree isn’t easy.

Trees are meant to grow tall and wide. It takes patience and careful effort to guide one into something miniature. Try to force it, and you’ll usually kill it.

Reef tanks are no different.

And that’s why the comparison works—because instead of a tree in miniature, you’re trying to build an ocean in miniature.

And one of those is a lot more complicated.

I was reminded of that recently watching a friend’s tank start to unravel before it ever really got its legs under it.

The problem was simple. My friend wanted a reef tank, but they were focused on the end result instead of the hurdles, the maintenance, and the overall journey it takes to get there.

Corals and plants feel similar on the surface, but they couldn’t be more different. The reason we want them in our tanks is the same, but they play very different ecological roles.

Plants are a stabilizing force. They act as a buffer for the animals in a freshwater tank. Corals are the complete opposite. Instead of stabilizing a tank, they rely entirely on the stability of a mature one.

A beautiful, thriving reef tank doesn’t happen overnight—and that’s where my friend struggled. The wrong types of corals were added far too quickly. Fish were crowded in before the ecosystem could catch up.

In freshwater, plants help buffer against issues like overstocking. Saltwater is far less forgiving. It’s generally fine… until it isn’t.

Ammonia is also more dangerous at higher pH. It takes much less to do real harm than it does in lower pH systems.

The cascade is where most people lose control. It’s rarely just one thing dying—it’s what happens next.

Corals are especially dramatic when they die. Being simpler animals, they can break down quickly, releasing more ammonia than the system can handle on short notice. That spike stresses or kills the weakest fish. Those fish then decompose, releasing even more ammonia.

And the cycle continues.

This chain reaction keeps going until everything is gone—or someone intervenes with a large water change.

Saltwater can feel unforgiving, even though it’s absolutely manageable.

The difference is time.

To build a system that can tolerate mistakes—and just the general messiness of life—you have to give it time. Patience is rewarded far more than quick action.

My reef might look like I’ve figured out some kind of balance, but it has far less to do with what I’ve done and far more to do with what I haven’t.

The real trick is making small changes and then waiting for the ripple to finish before doing anything else.

Add one fish. Wait for it to settle.

Maybe add another. Maybe add a coral instead.

Let the system respond before asking more of it.

Once a system is mature, it starts to handle itself.

It’s a long road to get there—but that’s where most of the enjoyment is anyway.

Most bonsai enthusiasts will tell you the same thing: the reward isn’t in showing off the tree.

It’s in the pruning. The shaping. The quiet, ongoing work of maintaining it. 

A reef tank isn’t something you finish.

It’s something you learn to tend.

There Was an Old Lady Who Swallowed a Tank

There's an old song about an old lady swallowing a fly. We don't know why she swallowed the fly. Regardless, to catch the fly, she swallowed a spider. To catch the spider, she swallowed a bird, then a cat, then a dog, and on and on until she attempted to swallow a horse. She's dead, of course. 

While it's meant to be nonsensical, it gives an interesting scope into how aquariums fail. 

A stable and flourishing ecosystem rarely collapses on its own. The biological engine of life doesn't turn on and off, it just keeps running. It must keep humming along without stop. When left undisturbed, an ecosystem runs in balance. 

The thing that crashes tanks is usually the tank's caretaker. Humans have a really hard time leaving things alone. It's especially stark maintaining an old and mature tank versus a brand-new and fragile tank. New tanks are heavily reliant on regular maintenance to not become toxic to aquatic life. Mature tanks quietly tick along without much intervention. 

Here's the problem that most people encounter. The fly is usually a small and seemingly insignificant decision. You don't notice a real problem until the horse kills it. 

I watched a video where a YouTuber takes you through his own beach paludarium crashing. He details how a few bad decisions compounded into a total collapse. It all starts with adding a fish he probably shouldn't have added. While it wasn't the fish itself that killed everything, this particular species needs to be fed constantly. Feeding was ramped up to accommodate. This caused extra nutrients to fuel algae. The algae was at risk for nuking the tank, so he added an urchin to eat it. The urchin worked too well and ate all the algae. Pest anemones and algae took over. He added a fish to take care of the pest anemones, which ate the remaining corals, too. The full collapse happened during a weekend out of town where his heater went down. 

Had he not kept trying to change things, the heater failure would have been buffered out. The ecosystem existing on a knifes edge can't take as many flies as the one that has layers of complexity baked in. Since, after all, we all swallow flies from time to time.

Sump it Up

Sumps are one of those things that quietly levels up your aquarium and no one talks about it. There's plenty of articles out there about sumps and how to build them. This isn't one of those. 

While I knew sumps were cool, until I had one, I didn't realize just how cool. 

A proper sump is literally an extension of your tank. Think of it less like more space and water volume and more like the engine compartment of a car. The magic happens in there that provides motion, AC/heat and even the radio. 

The allure of the sump happens in what's called the refugium. Saltwater is where this visually takes off, though a sump for freshwater can be just as powerful. The refugium is home to life that can't flourish with the fish, yet the fish depend on. Micro crustaceans, plants and algae, structure that provides a place for all of it. 

That’s really it. It sounds simple, but this is where things start to change.

The sump isn’t just extra water volume—it’s where biology takes over the job of filtration. Instead of relying on equipment to pull waste out, you’re giving the system a place to process it.

Copepods, sponges, amphipods, macro algae, worms, shrimp; the list goes on. One of the best feelings with a sump is seeing all the weird little lifeforms pop up that you didn’t even add, but were there the whole time, just quietly processing waste and nutrients.

It keeps the display clean, but more importantly, it keeps the system stable.

Room at the Table

One of the biggest tells I use for general fish health is more than just whether or not a fish eats. It's so much more than that. 

Take the Copper Banded Butterflyfish for example. The first week or two you have it, it's probably not going to eat. That doesn't mean that you should worry about it yet. 

In my tanks, I like to use feeding time as a roll call for my fish. The reef tank is really where this comes around. Most of the fish gather around the frozen cube of food I have held in my tongs, though some will never join the dogpile. Some hang back waiting for bits to fall off the cube. Some don't want to stray far from their hides. It's a general deviation from normal behavior that gets me worried.

My exquisite fairy wrasse is a good example. He settled in quick and is very food forward. He's almost always the first one at the cube. He'll often feel like he smashed into it with how quick he hits it. If he was hanging back for any reason, I would immediately notice something was off. He could still be eating for me to start to look for any changes in the tank. 

Other fish have a different vibe. My filefish sometimes likes to get in on the chaos and sometimes doesn't. I don't worry if I don't see him in the mob, but I do worry if I don't see him near. 

While not loud about it, fish can be very clear about something being wrong long before a problem becomes irreversible. Food time is your best baseline for that.