bam Demanding level

#11527 Cabin John Creek, Potomac River, Maryland, USA

Sponsored by

United States, Maryland, Montgomery County

Many hot summer days of my childhood were spent knee-deep in the cool waters of Cabin John Creek, chasing shiners and turning over rocks to find salamanders. I aimed to recreate the small branching tributaries of the Potomac River where they connect with the main body of the creek. My goal was to represent the muddy, often vertical stream banks that are frequently eroded into hollows where fish can seek shelter, supported by the roots of plants growing above.

Additionally, while working on the aquarium, I became increasingly interested in the impacts that human settlement has had on this body of water, ranging from eutrophication and litter to introduced species that have become naturally established. In short, I wanted to recreate the habitat as it exists today—not an idealized version of how it may have existed in the past.

Submitted by
Ryan Wright
GPS
39.0017586, -77.0951309
Geographical region
Northern America
Drainage Basin
Piedmont Plateau
River catchment
Potomac River
Water body type
Creek
Water body name
Cabin John
Water body part
Meander
Water body course
Middle course
Water body: tributary of
River
Tributary name
Potomac River

Videos above and below water


Warning: Undefined variable $fish_parent in /home/biotopea/public_html/wp-content/themes/bap/content-bam.php on line 85

Water Chemistry

Water information

Water type
Freshwater
Water color
Clear water
Water transparency
Medium
Concentration of sediments
Medium
Water temperature
23.9 °C
Water flow/curent
Strong

Chemical parameters

pH
Conductivity
300
GH
119 mg/l
dGH
KH
5 mg/l
dKH
Dissolved Oxygen

Aquarium information

Aquarium description

Set-up date
February, 2025
Aquarium decoration

The background was covered in stripes of aquarium-safe silicone to allow foam to adhere to the glass. The filtration intake and outflow were glued into position and incorporated into the design. From there, I built up layers of spray foam to create a convincing background and shoreline structure, using locally purchased spiderwood to mimic roots emerging from the stream bed.

The spray foam was trimmed to achieve the desired shapes, then coated with original formula Gorilla Glue, The Pond Guy’s Aquatic Planting Substrate, and coconut coir to replicate the silt and organic material that form the stream bed.

I then collected a variety of rocks from alongside the stream, likely including a mixture of calcite, sedimentary stones, and quartz, to represent the natural stone composition found within the creek. A few stones were collected directly from the creek to introduce native algae and biofilm, which are abundant in the habitat.

I also incorporated two examples of human-made debris that had become part of the creek environment: the neck of a broken glass bottle and a fragment of pottery. The relative health of the stream, despite its proximity to major highways, sources of eutrophication, and suburban development, is inspiring. This aquarium celebrates the way human activity and natural processes have developed a tentative coexistence in this ecosystem.

Aquarium equipment

Filtration: Aqua-El Max 1000

Heater: AquaTop 200 W Titanium Heater

Water Movement: Jebao SLW-5 Wavemaker

Aeration: Aquarium Co-Op Air Pump with Battery Backup

Lighting: Kessil A350WE LED Light

Fish care

After collection, the fish were treated with IntestiPro (a combination of praziquantel and metronidazole) for nine days to support gut health and reduce the risk of internal parasites.

The fish are fed twice daily, with a varied diet. Frozen foods include mysis shrimp, bloodworms, and Rod’s Food Freshwater Small Mouth blend. Dry foods include a variety of Fluval Bug Bites and New Life Spectrum Tropical Fish Formula. In addition, the aquarium was seeded with Moina macrocopa. Although this is not a native species, it was introduced to support the adaptation of the Tessellated Darters to aquarium conditions.

High oxygen saturation is maintained by positioning the Aqua-El filter outlet near the surface and using an additional air pump. Water movement is provided by a Jebao SLW-5 wavemaker, creating sufficient current for the fish to exhibit natural swimming behaviour.

Fish:

  • Etheostoma olmstedi (Percidae) – 4
  • Rhinichthys atratulus (Leuciscidae) – 4
  • Notropis amoenus (Leuciscidae) – 1
  • Gambusia holbrooki (Poeciliidae) – 1

Molluscs:

  • Ferrissia rivularis (Planorbidae) – 2
  • Physella acuta (Physidae) – 3
Plant care

The stream itself has minimal aquatic plant life; however, I found invasive starwort growing in the stream and allowed it to grow along the top of the aquascape, where it thrives with minimal maintenance. I ensure that the water level reaches the top of the aquarium and that the lights are on for 8 hours per day. Combined with the nutrients provided by the substrate, these conditions allow the plant to grow successfully.

Aquatic vegetation:

  • Callitriche stagnalis (Plantaginaceae) – 1
Water care

A 30% water change is performed twice per month, with replacement water treated with Seachem Prime. Seachem Alkaline Buffer is occasionally used as needed to maintain stable pH levels. Excess algae is regularly removed using a toothbrush during maintenance.

The filtration system is serviced monthly, using filter floss, biological sponges, ceramic biomedia, and ChemiPure Green.

Dimensions

Length
61 cm
Depth
33 cm
High
43 cm
Volume
75 L

Substrate in aquarium

Sand
None
Pebble/Gravel
Mixed
Stone
Mixed
Stone form
Irregular
Silt/Mud
Beige
Leaves
Few
Driftwood
Many
Submerged terrestrial vegetation
None