Shipwrecks are another popular type of fish tank decorations that a lot of hobbyists love to use and makes a perfect theme for any aquarium. This slideshow is taken from http://coolfishtankdecorations.com/shipwreck-fish-tank-decorations/

3. Penn Plax Shipwreck Resin Aquarium Décor
Resin with great detail.
Arches which fish love to swim
through. Sophisticated resin for
your aquarium.
Product Details Here

4. Helen C Shipwreck Ornament
Realistic boat for aquariums
from 24" to 48“
Product Details Here

5. Exotic Environments Shipwreck Bubbler
Aquarium Ornament
Exotic Environments Shipwreck
Bubbler Aquarium Ornament is
made with durable poly resin,
12-inch by 5-inch by 5-1/2-inch
Product Details Here

6. Exotic Environments Bow Shipwreck
Aquarium Ornament
Exotic Environments Bow
Shipwreck Aquarium Ornament is
made with durable poly resin,
13-inch by 9-inch by 10-1/2-inch
Product Details Here

7. Aquatic Creations Sunken Gondola Shipwreck
Aquarium Ornament
The Aquatic Creations Sunken
Gondola shipwreck ornament is
sure to bring attention to any
aquarium with its intricate
detailing and design. This is the
perfect accessory for any medium
sized aquarium and is made of
non-toxic, fish-safe materials and
colors.
Product Details Here

8. Exotic Environments Split Shipwreck
Aquarium Ornament
Exotic Environments Split
Shipwreck Aquarium Ornament is
made with durable poly resin
material safe for use in all
aquariums, Large, 11 inch by 5 inch
by 4-1/4 inch
Product Details Here

9. Penn Plax Finding Nemo Action Aerating
Resin Ornament
Finding Nemo- Action Aerating Resin
Ornament- Half Shipwreck. Half of a
ship with real shipwreck design.
Coloring and detail make this resin
very real looking.
Product Details Here

11. Blue Ribbon Sunken Humvee with Cave Ornament
Blue Ribbon Sunken Humvee with
Cave Ornament Exotic Environments
Humvee w/Cave - Frozen in time, this
sunken Humvee is what remains of a
once active military vehicle. Rusted
from the depths with a revealing cave,
your aquarium inhabitants will relish
the dark hiding place and safe haven
it provides. Product Features: It is the
remains of a once active military
vehicle. Item Specifications:
Dimensions: 3.75" L x 1.75" W x 2" H
Product Details Here

12. Aquascaping Sunken Military War Tank Ornament
These long-lasting and beautiful
ornaments are made of fade-resistant
and non-toxic material. Safe for aquatic
life. Your fish will love them, these
aquarium ornaments enhance visual
appeal and provide ample shelter for
your fish to swim and hide. Use these
ornaments to create a beautiful
undersea world and spark your
imagination. Easy to clean and suitable
for both salt and fresh water.
Product Details Here

13. Deep Blue Professional Wwii Sunken Aircraft
With Wing Segments
Deep Blue DecoConcepts Sunken
WWII Airplane 24in
Product Details Here

14. Blue Ribbon Pet Products Exotic Environments
Sunken Helicopter Aquarium Ornament
The exotic environments super sized
aquarium ornaments are hand painted
heavy duty resin and safe for all
aquariums. These made ideal places
for your tropical fish to hide and feel
safe in addition to being a beautiful
addition to any aquarium.
Product Details Here

15. Blue VW Camper Van
VW camper Van in Blue, attach air
pump to see bubbles coming out of
Muffler / Exhaust
Product Details Here