While we wait for our tank to cycle, we have plenty of time to obsess over the most fun part of fishkeeping: choosing the fish.
Our goal was a peaceful community tank with fish that would thrive in our soft water (3 dGH) and work well with the Walstad method. After considering dozens of species and several complete plan rewrites, we settled on a combination that we’re genuinely excited about.
The Soft Water Advantage
When we tested our tap water, we discovered it’s quite soft—3 dGH (general hardness) and 5 dKH (carbonate hardness). This is perfect for fish from blackwater environments like the Amazon, but it ruled out some species that need harder water.
Our coral hardscape might slowly raise these numbers over time, so we’ll monitor and adjust as needed.
The Final Stocking Plan
Upper/Mid Level: Cardinal Tetras (8)
These electric blue and red jewels will be the stars of our tank. Cardinal Tetras have a brilliant neon blue stripe running from nose to tail, with bright red coloring along the lower half of their body.
Why we chose them over Neon Tetras: Cardinals have red that extends the full length of their body (vs. only the rear half in Neons), and they prefer slightly warmer water that matches our planned temperature of 75-76°F.
Key stats:
- Size: 1.5-2 inches
- Lifespan: 4-5 years
- Behavior: Tight schooling, always moving together
Mid Level: Chili Rasboras (6)
These tiny jewels (only 0.6-0.8 inches!) add a deep ruby red accent to the middle of the tank. They’re one of the smallest aquarium fish available, which makes them perfect for adding activity without adding bioload.
Chili Rasboras are peaceful micro-predators that will dart through our Water Wisteria stems hunting for copepods and other tiny creatures.
Bottom Level: Pygmy Corydoras (4)
Pygmy Corys are adorable miniature catfish that school together and forage along the bottom. Unlike larger corydoras that can disturb substrate, these tiny guys (under an inch) are gentle on our sand cap.
They’re social, active during the day, and will add life to the bottom zone that might otherwise be overlooked.
The Cleanup Crew: Cherry Shrimp (10-15)
This was a late addition to our plan—and possibly the best decision we’re making.
Originally, we considered Honey Gouramis as a centerpiece fish. But Honey Gouramis are known to snack on shrimp, and we really wanted a breeding shrimp colony. So we dropped the gouramis and added Cherry Shrimp instead.
Why shrimp are amazing:
- Constantly foraging, cleaning every surface
- Beautiful bright red color against green plants
- They breed readily—we’ll have a self-sustaining colony
- Low bioload means minimal impact on water quality
- Absolutely fascinating to watch
Algae Patrol: Nerite Snails (5)
Nerite snails are the gold standard for algae control. They can’t breed in freshwater (no population explosions), they eat all types of algae, and they come in beautiful patterns.
We’re planning to add our first 3 Nerites early—once parameters stabilize around Day 13-14—because they’re hardy enough to handle cycling conditions and can help with biofilm buildup.
The Complete Picture
| Species | Quantity | Swimming Level | Purpose |
|---|---|---|---|
| Cardinal Tetras | 8 | Upper/Mid | Schooling show fish |
| Chili Rasboras | 6 | Mid | Accent color, activity |
| Pygmy Corydoras | 4 | Bottom | Foraging, personality |
| Cherry Shrimp | 10-15 | Bottom/plants | Cleanup, breeding colony |
| Nerite Snails | 5 | Bottom/glass | Algae control |
Total: 18 fish + 10-15 shrimp + 5 snails
This is a light bioload for a 20-gallon tank, which is perfect for the Walstad method. The plants need time to establish before handling heavy fish waste loads.
The Stocking Timeline
We’re not adding everything at once—that would be a recipe for ammonia spikes. Our plan:
- Month 1 (Cycling): Add Nerite snails once parameters stabilize
- Month 2: Add Cardinal Tetras (first fish!)
- Month 2-3: Add Cherry Shrimp
- Month 3: Add Chili Rasboras
- Month 4: Add Pygmy Corydoras (final addition)
Each addition gets 1-2 weeks of monitoring before the next. Slow and steady wins the fishkeeping race.
Budget for Livestock
| Species | Quantity | Est. Cost |
|---|---|---|
| Cardinal Tetras | 8 | $32-56 |
| Chili Rasboras | 6 | $18-24 |
| Pygmy Corydoras | 4 | $16-24 |
| Cherry Shrimp | 10-15 | $20-45 |
| Nerite Snails | 5 | $12-20 |
| Total | $98-169 |
What We’re Most Excited About
Honestly? The shrimp. There’s something magical about having a breeding colony—watching tiny shrimplets appear and grow, seeing the females carry eggs, observing their constant foraging behavior.
The Cardinal Tetras will be the visual centerpiece, but we suspect the Cherry Shrimp will steal our hearts.
The Waiting Game
Of course, none of this happens until the tank is fully cycled. The anticipation is killing us, but we know patience now means a healthy, stable tank for years to come.